Pain after sex or masterbation

So I’ve only had sex 2/3 times and after my stomach would cramp and hurt for a good few days after. The same with if I masterbate and use something to penetrate myself.

It’s really uncomfortable and quite painful, even masterbating I’ve tried difference speeds, how far I insert my toy and angles and no matter what it always hurts after.

Anyone else have this problem? And know what it could be? I feel somewhat embarrassed by it cause I can’t gain any pleasure without a lot of pain after!