Being in constant severe pain and not being able to tell your parents or doctor what's happening must really suck. The words and the emotions are there, but they can't come out. It's not your fault, it's just the way you were made.
Man. Talk about frustrating. I feel for ya, kid...I don't know how you put up with it. If it was me, I'd probably be biting myself and everyone around me too.
Hang in there.