Shoulder pain is a symptom rather than a condition in itself. There are a number of causes behind shoulder pain, which can be either severe or ongoing (lasting more than two weeks).

The most common causes of shoulder pain include shoulder disorders such as:

• Frozen shoulder.
• Rotator cuff disorders.
• Shoulder instability.

These disorders are explained in this article, but it does not cover acromioclavicular joint disorders, glenohumeral joint arthritis, osteoarthritis, or fracture (broken bone). See Useful links for information about arthritis, osteoarthritis and broken bones.

If you have severe or ongoing shoulder pain, it is important to get the correct diagnosis from your GP. You can then receive effective treatment for your pain.

In most cases, shoulder disorders improve with time by following the relevant treatment advice.

Shoulder pain can be caused by a number of conditions, including frozen shoulder, rotator cuff disorders or shoulder instability disorder.

Frozen shoulder

Frozen shoulder is a condition that affects your ability to move your shoulder. It is also known as adhesive capsulitis. Most cases of frozen shoulder occur in people between 40-60 years of age, and the condition is more common in women than in men.

Frozen shoulder occurs when there is thickening, swelling and tightening of the flexible tissue surrounding your shoulder joint. This leaves less space for your upper arm bone (humerus) in the shoulder joint, and makes any movement stiff and painful.

What causes frozen shoulder?

The exact cause of frozen shoulder is not fully understood. However, there are several risk factors that make developing frozen shoulder more likely. These are outlined below.

Shoulder injury or surgery

Frozen shoulder may occur if you keep your arm and shoulder still for long periods of time, for example, while you recover from an arm injury or arm surgery. Your GP can give you advice if you have a shoulder injury or need to have shoulder surgery.

Diabetes

You are two to four times more likely to develop frozen shoulder if you have diabetes, but the exact reason for this is unknown. If you have diabetes, you are also more likely to develop the condition in both your shoulders, and your symptoms may be more severe.

Other health conditions

Other health conditions that can lead to an increased chance of getting frozen shoulder include:

• Heart or lung disease.
• An overactive thyroid gland (hyperthyroidism).
• Parkinson’s disease (a chronic neurological condition).
• Dupuytren’s contracture (shortening of connective tissue in the hand).
   

Rotator cuff disorders

The rotator cuff is a group of muscles around the shoulder joint, which help to keep the joint in the right position, and allow it to move in a controlled way. Each muscle has a tendon, and they join together to form the rotator cuff tendon.

Your rotator cuff can be affected by:

• Tendonitis.
• Bursitis (inflammation around a joint).
• A tear.

What causes rotator cuff disorders?

Rotator cuff tendonitis is a result of irritation and inflammation of the tendon, usually caused by a shoulder injury or overuse of the shoulder. For example, the condition may affect someone whose job requires a lot of overhead lifting, or an athlete who competes in sports that involve throwing.

Impingement syndrome occurs when the rotator cuff tendon becomes trapped in the space beneath the shoulder blade. The tendon is repeatedly scraped against the shoulder blade, which causes it to slowly deteriorate and weaken. Sometimes, the tendon will tear.

Tendon tears are most common in people who are over 40 years of age. Tears in younger people are usually caused by an accident. In older people, tears are usually caused by impingement syndrome.

Shoulder instability

The shoulder joint is a ball and socket joint. The top of your upper arm bone (humerus) is the ball, which fits into the socket of your shoulder blade.

Shoulder instability occurs when the ball part of the shoulder joint does not move correctly in the socket. This can range from a slipping or ‘catching’ feeling in your shoulder, to a full dislocation (where the ball comes completely out of the socket).

Shoulder instability can be either:

• Traumatic: the shoulder is forced out of place by a sudden impact.
• Atraumatic: the shoulder gradually moves out of place over time.

Traumatic shoulder instability is often the result of an accident. Atraumatic instability tends to occur as a result of repetitive arm movements, such as throwing or swimming.

The type of shoulder pain that you experience depends on the type of shoulder condition that you have. For example, you may experience pain in different areas of your shoulder, and particular arm movements may cause it. The pain can also be accompanied by other symptoms.

Symptoms of frozen shoulder

Frozen shoulder is a painful, persistent stiffness of the shoulder joint, which makes it very difficult to carry out the full range of normal shoulder movements.

You may find it hard to carry out everyday tasks, such as dressing, driving, and sleeping comfortably. Some people find they are unable to move their shoulder at all.

Symptoms of frozen shoulder advance slowly and they are usually experienced in three stages, which are spread over a number of months or years. Symptoms can vary greatly from person to person.

The three stages of frozen shoulder are outlined below:

Stage one

During stage one of frozen shoulder, your shoulder starts to ache and feel stiff, and then becomes very painful. The pain is often worse at night, and when you lie on the affected side. Stage one usually lasts between two to nine months.

Stage two

Stage two of frozen shoulder is known as the adhesive stage. Your shoulder becomes increasingly stiff but the pain does not normally get worse. The muscles may start to waste slightly as they are not being used. Stage two lasts between four and twelve months.

Stage three

Stage three is the recovery stage where you gradually regain movement in your shoulder. The pain also fades, although it may recur from time to time as the stiffness eases.

Following frozen shoulder you may not regain full movement of your shoulder, but you will be able to do many more tasks. Stage three can last from five months to four years.

Rotator cuff disorders

The symptoms of the different rotator cuff disorders are generally quite distinct.

Tendonitis: the pain is sudden and is worse during activities that involve your arm being above shoulder level, for example, when brushing your hair.

Impingement syndrome: the pain tends to be chronic, and is usually worse during overhead activities and at night.

Tear: the pain is usually over the front and outer area of your shoulder, and is worse when your arm is above your head and when reaching forward. If you have a tear, your arm and shoulder can feel very weak, and some people feel a clicking sensation.

Shoulder instability

The symptoms of shoulder instability can sometimes be vague. However, the following symptoms are often reported as similar to having a ‘dead arm’. Descriptions include:

• Tingling.
• Weakness.
• Numbness.
• Shoulder fatigue (tiredness).
• A clicking, locking or popping sensation.

If the shoulder is dislocated symptoms can include:

• Pain (which can sometimes be severe).
• The arm being visibly out of position.
• Swelling.
• Bruising.

You should see your GP if you have experienced any kind of shoulder pain for more than two weeks.

Discussing your symptoms

If you go to your GP with shoulder pain, they can often diagnose the cause of the pain by discussing your symptoms with you.

They will need to know whether you have had any recent injuries, whether anything makes the pain feel better or worse, and whether the pain is worse at night.

Physical examination

Your GP will probably carry out a physical examination of your shoulder area. They will compare your shoulders and check for any redness or swelling on the painful side. They will also check if your arm is dislocated. If it is, your shoulder will be in an unusual position.

Arm movements

Your GP is also likely to ask you to do some specific arm movements. The type of movements that cause you pain will enable them to work out what is causing it.

X-ray

If the inside of your shoulder joint needs to be examined in order to rule out other damage, you may have a shoulder X-ray or a magnetic resonance imaging (MRI) scan. If you need to have an X-ray or MRI scan, your GP will refer you to your local hospital.

There are several forms of treatment for shoulder pain and they vary slightly, depending on the cause of the pain. The main treatment options include:

• Rest.
• Painkillers.
• Anti-inflammatories.
• Ice packs.
• Physiotherapy.
• Surgery (in some cases).

Painkillers

If your pain is mild, taking painkillers such as paracetamol or codeine may be enough to control it. You should always follow the dosage instructions on the packet to ensure that you don't take too much.

If your shoulder pain is more severe, your GP may recommend or prescribe an anti-inflammatory painkiller, such as ibuprofen, diclofenac or naproxen.

As well as easing the pain, these painkillers can also help to reduce swelling in your shoulder capsule. They are most effective when taken regularly, rather than when symptoms are most painful.

Side effects sometimes occur with anti-inflammatory painkillers. Before taking anti-inflammatory painkillers, you should consult your GP if you have asthma, high blood pressure (hypertension), kidney problems or heart problems.

Corticosteroid injections

If your shoulder pain is very severe, such as in certain cases of frozen shoulder, treatment using painkillers may not be enough to control the pain. In this case, you may have corticosteroids injected into and around your shoulder joint. Corticosteroids are medicines that help to reduce swelling and pain.

Corticosteroid injections are very effective at relieving symptoms of frozen shoulder for several weeks at a time, particularly during the first stage of symptoms. However, the injections will not be able to cure your condition completely, and your symptoms will gradually return.

Also, having too many corticosteroid injections can damage your shoulder, so you may only be able to have this type of treatment once or twice.

Shoulder exercises

If you have shoulder pain, it is important to keep your shoulder joint mobile by doing gentle, regular exercise. Not using your shoulder can cause your muscles to waste away, and may make any stiffness worse. Therefore, if possible, you should continue using your shoulder as normal.
If your shoulder is very stiff, exercise may be painful. Your GP or physiotherapist will be able to give you some exercises that you can do without causing further damage to your shoulder.

Alternatively, you may have shoulder manipulation under a general anaesthetic, where your shoulder is gently moved and stretched while you are asleep.

Physiotherapy

If you are referred to a physiotherapist, you may have treatments such as massage, thermotherapy with warm or cold packs, or transcutaneous electrical nerve stimulation (TENS).

TENS is a type of physiotherapy where small electrical pads (electrodes) are applied to the skin over your shoulder. The TENS machines delivers small pulses of electricity through the electrodes, which numb the nerve endings and control your pain.

Reduction

If you have a dislocated shoulder, it will need to be put back in place by the doctor. They will put the ball of your upper arm bone (humerus) back into the joint socket. This procedure is called a reduction.

After a reduction, you will need to rest your arm by wearing a sling for about three weeks. Applying an ice pack (with a cover on it to protect your skin) can help to reduce the pain.

Your physiotherapist will be able to show you exercises that will help you to regain strength in your shoulder muscles.

Surgery for frozen shoulder

If other treatments for frozen shoulder have not worked, you may be referred for surgery. Your surgeon can remove any bands of scar tissue that may have formed in your shoulder capsule. This will greatly improve your symptoms.
If you need to have surgery for frozen shoulder, it is likely that you will have an operation known as an arthroscopic capsular release. This is a type of keyhole or non-invasive surgery, which means that the surgeon will carry out the procedure after making an incision (cut) that is less than 1cm long.

You will need to have physiotherapy after your operation to help you regain a full range of movement in your shoulder joint.

Surgery for a rotator cuff tear

Around 50% of rotator cuff tears require surgery. Surgery is usually needed when the tear in the rotator cuff tendon is very large. This operation can be performed using either keyhole or open surgery.

As with frozen shoulder surgery, you will need to have physiotherapy after your operation in order to help you regain a full range of movement in your shoulder joint.

Surgery for shoulder instability

If your shoulder dislocates regularly or severely, you may need to have surgery to prevent it happening again, and to protect the surrounding tissues and nerves from becoming damaged.

Surgery involves tightening stretched ligaments or reattaching them if they have torn.

Surgery for shoulder instability can either be done using keyhole or open surgery. After the operation, your shoulder needs to be immobilised (prevented from moving) using a special sling for about six weeks. A full recovery can take a number of months.