What Causes Bruising And Pain In Between The Thighs And Groin Area?

Hi. I ve had pain whenever i move right in the inner area between my thigh and my crotch. And i saw today it was a bruise. But i don t remember ever getting hit there or anything like that. I think there is a lump like an inch or two away under the skin but i cant be sure if its even related to it. Any explanations? Thanks!