MODEL RELEASED. Elbow pain. Man holding his painful elbow. The pain could be caused by over- use of the tendons that connect muscles to the elbow bones. The tendons swell, causing pain and tenderness in the joint. This type of repetitive strain injury (RSI) is known as epicondylitis, or tennis elbow. The symptoms can be treated by applying ice-packs or taking anti-inflammatory drugs. The only cure is to rest the elbow.