This is possibly one of the most frequent injuries I see so I thought it may be of benefit to review.
Inflamation of one or both of the epicondyles tendons that connect forearm muscles to the elbow.
This is mostly caused from weak wrists and forearms, and if not treated properly can require months to heal and in some cases cause complete tears requiring surgery.
So...
Warm up properly.
Train your wrists and forearms.
If you have any tendon injury remember that they have poor blood flow so healing is going to be slow. Ice massage for inflamation and following that heat treatments and anti-inflamatorys...but mostly if it hurts then give it a rest.