Pelvic Floor Pain

Hi 31 F here, I am having pelvis pain for the past 3 years. It starts after my periods, and i feel cramps like period cramps after having sex or even orgasming.

It started three years back and have even got my self checked. All my ultra sounds all my hormonal blood tests were normal.

Once the pain starts, it last for 10 mins or so and then goes away. Somehow the only time i fe relief is when i get my periods, what might be causing this? Does anyone have similar issue?