Frozen shoulder (adhesive capsulitis) is a disorder in which the shoulder capsule, the connective tissue surrounding the glenohumeral joint of the shoulder, becomes inflamed and causes persistent stiffness of the shoulder joint, which makes it very difficult to carry out the full range of normal shoulder movements and everyday tasks such as dressing and driving.

Pain is usually constant and worse at night, making it impossible to sleep comfortably, and in the winter when the weather is colder. Some people find they are unable to move their shoulder at all, which is why the condition is known as a frozen shoulder.

The exact cause for frozen shoulder is unknown and it can last from five months to three years or more. It is thought in some cases to be caused by injury or trauma to the area; it is most common in people between the ages of 40 and 60 and is more common in women than men.

There are three stages in the development and recovery of frozen shoulder:

1. Initially, your shoulder will start to ache and will feel stiff before becoming very painful. The pain is often worse at night and when you lie on the affected side. This stage can last from two to nine months.
2. Stage two – the adhesive stage – is where the shoulder becomes increasingly stiff while the pain stays about the same. Shoulder muscles may waste slightly due to less use. This stage lasts four to twelve months.
3. The recovery stage, during which gradual movement in the shoulder is regained and the stiffness eases. The pain will also begin to fade. This stage can last for as little as five months or as long as three to four years.