Shoulder pain caused by connective tissue, called a tendon, rubbing on a shoulder bone.

The cause of the pain of impingement syndrome is a tendon rubbing against a bone at the top of the shoulder, called the acromion. Repeated overhead arm movements, such as throwing a ball, swimming or painting, can be a cause. Injury and aging are other causes.

Symptoms include pain that increases with reaching, overhead movements, throwing and sleeping on the side that's affected. There also can be loss of strength and ability to move the arm and shoulder, especially when the arm is held overhead.

Rest, nonsteroidal antiinflammatory medicines and physical therapy can help. If those don't help, a steroid medicine mixed with a numbing medicine might be used. The medicine is put into the area with a needle. If nothing else helps, treatment might involve surgery.