Shoulder injuries are frequently caused by athletic activities that involve excessive, repetitive, overhead motion, such as swimming, tennis, pitching, and weightlifting. Injuries can also occur during everyday activities such as hanging curtains and gardening.

Shoulder injuries are frequently caused by athletic activities that involve excessive, repetitive, overhead motion, such as swimming, tennis, pitching, and weightlifting. Injuries can also occur during everyday activities such as hanging curtains and gardening.

Some people will have a tendency to ignore the pain and “play through” a shoulder injury, which only aggravates the condition, and may possibly cause more problems. People also may underestimate the extent of their injury because steady pain, weakness in the arm, or limitation of joint motion will become almost second nature to them.

http://orthoinfo.aaos.org/topic.cfm?topic=A00327