The best recommendation would be to see a professional.
It may be the result of general overuse, common with tennis players who experience tennis elbow - lateral epicondylitis or medial epicondylitis.
Quote: "Elbow epicondylitis is not limited to those persons playing tennis, golf, baseball or swimming and can result from any activity that puts the lateral or medial compartments of the elbow under similar repetitive stress and strain (e.g., hammering, turning a key, screw driver use, computer work, excessive hand shaking)."
The following provides some useful information with treating tennis elbow:
They suggest specific phases for recovery. The first being Rest, Ice, Compression and Elevation.
The second phase is stretching and strengthening.
Hope that helps.