A 37-year-old male experienced acute pain in the right shoulder while watching television 5 months ago. There was no history of trauma except that a week prior he was running in the airport carrying a 20-pound computer bag. The pain was dull and throbbing. Then he noticed difficulty with overhead movements. The pain subsided over 4 days. The arm movement slightly improved but is still significantly impaired. There is no tingling or numbness.