Sometimes (about 50% of the time) after sex, my girlfriend will experience stomach pains. We've tried everything from making sure she's as aroused as possible to going slow and gentle but the pains still occur.

We've noticed that when we have sex more frequently the pains occur less after awhile. I've wondered before if it's a result of me hitting something inside of her as she has a relatively small build and my penis is kind of large for her.

At rare instances during sex we'll have to stop because she'll start having pains. These pains occur especially when I go deep. I always make sure shes wet enough and aroused enough before going into her so I don't think that that's what's causing this.

I just wanted to see if there's anything I could do so she won't have to experience these pains anymore. Is this a medical condition she should have checked out?