The golf swing is a common source of pain on the inside bump of the elbow, the medial epicondyle. Repeating the golf swing over and over can begin to put a strain on the flexor tendons of the forearm where they attach to the medial epicondyle. Eventually, these repeated strains can produce pain on the inside edge of the elbow. Commonly called "golfer's elbow," the medical term for this condition is medial epicondylitis.
However, any activity that puts a similar strain on the forearm flexor tendons can produce symptoms. For example, shoveling, gardening, and hammering nails can all cause medial epicondylitis.