With all due respect to the medical minds that reside here, I wouldn't be following any of their advice about repetitive strain injuries.
I have had pretty much every musculoskeletal injury I think it is possible to have in the last 10 or 12 years, and their advice is next to useless, unless, as Rich points out, it is to check whether there is something else wrong.
You need to find a decent, old school physio. Not one of the nancy boys they churn out of universities these days, but an old style one who believes in the basics of deep tissue massage and stretching.
Find someone who knows how to dig into you properly, and gives you two or three decent stretches, and then some strength work to follow up, and you will be as right as rain.
For medial epichondylitis, you can't go wrong by facing a wall, placing the palm of your injured limb against the wall at chest height to start, then slowly turning away until you feel a mild stretch along the inner forearm. Hold it for a minute, rest thirty seconds, then do it again, maybe with your palm a little higher on the wall this time.
Do it every hour while you are awake, and I guarantee it won't take long to go.