I used to get it on the outside rear, so more pushing work, especially extensions really hurt like a tooth ache.
Is there any black and blue marks around the area?
For mine, I would do all the trigger points in upper and lower arms, even shoulders and then stretching and rotating.
I made sure I was getting some good supp. magnesium.
Are you using creatine?
Steer clear of the stuff that aggravates it for a few weeks perhaps!?