Sounds like a little tendonitis.
I'm no doctor, but I think you've "over-used" the muscles on the inside of your elbow or on the bottom of your forearm, while "under-using" or under developing the muscles on the outside of your elbow or the top of your forearm.
If you massage around your forearm and elbow you my be able to feel some tightness, or even some knots. Keep massaging until you kinda work things out.
Ice where ever it hurts, or where ever you find tight spots.
Try using the wrist roller in your training. If you roll forwards and backwards you'll work all the muscles in your forearms evenly. Also, the wrist roller works to stretch out all your forearm muscles. This helps a lot.
Avoid tricep extension movements, especially skull crushers for awhile.