I had tendonitis a little over a month ago and it really affected my lifts. My tendonitis was focused mainly in my tricep tendons so it really hurt when I did any type of "push" tricep exercises with the pain residing on the inside part of my elbow.

I'd recommend going to your doctor just to play it safe, if anything he will just make you take it easy for a few weeks on the exercises that affect it if it tendonitis. It is pretty common in weight lifting as the tendons become overused and stressed from heavy weights. Better to go and get it checked out than to make it worse, especially if its a small tear or so forth.