How could my doctor diagnose my elbow pain as tennis elbow? I've never even played the game.

Lateral epicondylitis, commonly known as tennis elbow, is not limited to tennis players. The backhand swing in tennis can strain the muscles and tendons of the elbow in a way that leads to tennis elbow. But many other types of repetitive activities can also lead to tennis elbow--painting with a brush or roller, running a chain saw, and using many types of hand tools. Any activities that repeatedly stress the same forearm muscles can cause symptoms of tennis elbow.