Boring.

I love having sex with my boyfriend but I feel like it's getting boring because of me. A year ago I started gettig really bad pelvic pain and to this day it hurts to have sex sometimes. If I do it in different positions it hurts more so we mostly only do it while I'm on my back.  I'm afraid to do anythig else because it hurts so bad but he is getting really annoyed and I feel like he doesn't want to have sex with me anymore. Idk what to do... Let him hurt me and do something different, or continue as we have been?