What Causes Raised Bumps On Inner Buttocks?

I feel what seems like welts or raised bumps on my inner butt cheeks. Nothing bleeding, swollen, red or white. I cannot tell for sure if I'm experiencing a rash or is it stretch marks? I'm sudden;y worried because I have been experiencing a lot of hives this past month. I don't know if I could get an allergic response around my butt whole.