Elbow pain in bodybuilding is very common and almost unavoidable. It is almost always due to tendonitis-either lateral or medial epicondylitis (golfer's and tennis elbow). The problem is even worse when using AAS that strengthen the muscle while doing little for the tenodns and ligaments. You are actually creating micro tears in the tendon where it inserts on the elbow. Obviously not doing the exercises that irritate and resting will help. Avoid corticosteroid injections into the area as they will take the pain away but will weaken the tendon making you prone to rupture (especially triceps tendon) and other problems. There is a treatment called prolotherapy that will actually strenghten the the tendon. Do a google search to educate yourself so I don't have to be so wordy. I had it done and it works. You can also wear the bands that constrict the forearm muscles when training.
Triceps tendonitis will be excruciating with exercises such as skull crushers, you will immediately if this is the problem. If so, it's time to rest!!
If you have not figured it out, I'm a physician.
Good luck.