is it normal to cramp while having sex?

I don't know I know I always get cramps after sex

I mean afterwards I'm fine and she starts moving around again, but it just hurts and my stomach gets really hard and bulgy where she's at

Yeah it's normal it always happens but normally your uterus is so small you don't really feel them.

see mine hurts like it's gets to where I can't move

Yep....make sure u stay hydrated through out the day since sex obvi uses the body's fluids for lubrication u will cramp faster

yes, because your muscles are contracting.