Need answers and advice....

I would say my boyfriend is pretty average maybe a little bigger then average but it hurts when we have sex but only when he goes deep like to the point where I want to pull away or sometimes it can be unbearable but then there’s times where it don’t bother me at all... but the times that it does it’s like whatever part he was hitting that was hurting is still hurting even after we’re done idk if this is normal sometimes I scare myself thinking stuffs wrong with me but I’m to scared/uncomfortable to go to the gyno.