Sounds like medial epicondylitis. Google that for more info to see if its what you have
General tendonitis prescription:
1. Rest. Especially if it's JUST mild overuse. If it's chronic then pure rest may not help.
2. Ice after any use & when sore. 15-30 mins per sessions for couple times a day. Direct ice massage ON the skin works the best.
3. Light stretch, not painful for agonists; strengthen antagonists. So stretch flexors, strengthen extensors *until* pain subsides (medial epicondylitis -- opposite for lateral epicondylitis). Then strengthen everything (my pref = rice bucket)
4. Self massage... cross friction and myofascial release the whole area inbetween both joints that surround it (shoulder to wrist for medial epicondlyitis; ankle-hip for something knee; etc.). As much as possible... at least 30 mins a day if not more. Also, tennis ball/golf ball areas & foam roll
5. Anti-inflammatories/NSAIDs. Fish oil is a good one.
6. Stay away from painful exercises. Period. It hurts, don't do them. Should be obvious but people don't listen.
7. Light eccentric exercises tend to help ESPECIALLY if the muscle(s) aggravated cannot smoothly do it.
8. + joint/cartilage health supplements like glucosamine & chondroin sulfate, MSM, shark, etc. Might be a good idea to start eating the cartilage and tendons off your meat too.