I found a pea sized lump under my skin in the area... Well, at the top of left butt cheek almost in the crack. It's weird because I can't see the lump, but if I feel around there I most certainly can make out it's roundness under the skin. However, on the skin there is a very, very small purpleish blotch. This isn't oozing anything gross and nothing happens if I try to squeeze it. It's actually almost visibly unnoticable. However, it *is* painful to sit on. Typically when I sit on the floor I tend to lean back a bit and sit on the upper part of my buttocks. At first I thought it might be something like a pustule or nodule, but then that's a weird spot for me to have those things show up. Any input?