Shoulder pain is an extremely common complaint affecting around three in ten adults at some time during their lives. There are many common causes of this problem and it is one of the more common reasons for physician visits for musculoskeletal symptoms. The shoulder is the most movable joint in the body and is also one of the largest and most complex joints in the body. A group of four tendons in the shoulder, called the rotator cuff, give the shoulder a wide range of motion. This range of motion cause the shoulder to be one of the most unstable joint in the body. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well.