You may not recall having a specific injury, especially if symptoms began gradually or during everyday activities. Overuse injuries occur when too much stress is placed on a joint or other tissue, often by overdoing an activity or through repetition of an activity. Overuse injuries include:

• Inflammation of the sac of fluid that cushions and lubricates the joint area between one bone and another bone, a tendon, or the skin (bursitis).
• Inflammation of the tough, ropy fibers that connect muscles to bones (tendinitis). Bicipital tendinitis is an inflammation of one of the tendons that attach the muscle (biceps) on the front of the upper arm bone (humerus) to the shoulder joint. The inflammation usually occurs along the groove (bicipital groove) where the tendon passes over the humerus to attach just above the shoulder joint.
• Muscle strain.
• A frozen shoulder, which is a condition that limits shoulder movement and may follow an injury.
• Overhead arm movements, which may cause tendons to rub or scrape against a part of the shoulder blade called the acromion. This rubbing or scraping may lead to abrasion or inflammation of the rotator cuff tendons (also called impingement syndrome).

Other causes of shoulder symptoms

Overuse and acute injuries are common causes of shoulder symptoms. Less common causes of shoulder symptoms include:

• Muscle tension or poor posture.
• Pain that is coming from somewhere else in your body (referred shoulder pain).
• Breakdown of the cartilage that protects and cushions the shoulder joints (osteoarthritis).
• Calcium buildup in the tendons of the shoulder.
• An irritated or pinched nerve or a herniated disc in the neck.
• Infection in the skin (cellulitis), joint (infectious arthritis), bursa (septic bursitis), or bone (osteomyelitis).
• Invasive cancer that has spread to the bones of the shoulder or spine.
• Abuse. Any shoulder injury (especially a dislocated shoulder) that cannot be explained, does not match the explanation, or occurs repeatedly may be caused by abuse.

Treatment

Treatment for a shoulder injury may include first aid measures, physical therapy, medicine, and, in some cases, surgery. Treatment depends on:

• The location, type, and severity of the injury.
• How long ago the injury occurred.
• Your age, health condition, and activities, such as work, sports, or hobbies.

Check your symptoms to decide if and when you should see a doctor.