I posted a similar question a month or so ago in the Shooters Form Forum. The advice I received is much like what you are getting here now. Some say Tendonitis, and there is another thread here today that discusses Bursitis. My experience is that I was exercising repetitively (using a heavy ball too much) and that caused inflammation in my left elbow. I also found that my bow string had stretched about 1/4" and the hand shock was pretty severe. I twisted my string to a proper brace height, quit doing the repetitive exercising, iced it, plenty of Tylenol and rested the arm. I've started shooting again and it does feel much better. Probably the best thing you can do is visit your doctor.