I am a 42-year-old woman who developed pain in my right shoulder about eight months ago. The pain is sharp and knifelike and often wakes me up at night. I play tennis several times a week, which does not seem to make the pain any worse, and I do not recall injuring myself. I have been hoping that the pain would go away on its own but that does not seem to be the case. What do you think is causing this?

Symptoms of sharp, knifelike pain is often reported when the shoulder's rotator cuff, tendon and bursal tissue are inflamed. Repetitive activities that stress the shoulder can result in an overuse syndrome. The tendon and bursal tissue respond to the overuse by becoming inflamed. The resulting symptoms can include not only pain, but weakness and reduced range of motion. Increased severity of pain at night in the shoulder comes from compression of the tendon and bursal tissue. These tissue structures are compressed between the bone of the shoulder blade (acromion) and the head of the humerus bone of the arm. When one rolls onto the side of the shoulder, this compression occurs, resulting in pain. This nightly stimulation, coupled with repeated overuse activities, can be a source of a chronically inflamed shoulder. In the majority of cases, these symptoms can be treated by nonoperative methods. These include anti-inflammatory medication, cessation of the overuse activity and physical therapy. When the nonoperative treatment fails, shoulder surgery can be very effective in relieving these symptoms.