M.D. The rotator cuff muscles hold the head of the long bone of your upper arm tightly in the socket of your shoulder. Sports that require moving the arm over the head repeatedly can cause tearing and swelling of the tendons of these muscles. Baseball pitchers, swimmers, weight lifters and tennis players often suffer this injury.
Chronic irritation can cause pain, swelling and tearing of the rotator cuff.
If you continue to exercise in spite of the pain, you will tear the tendons from their attachments. Initially, pain occurs only when you hold your arm over your head and bring it down or forward forcibly. Later, it will hurt when the arm is moved forward for any reason, such as to shake hands. Usually, it hurts when you push things away and does not hurt when you pull objects toward you. A torn rotator cuff will cause tenderness over the tendons, especially when the elbow is raised above the shoulder.