Hello. I m sorry you re uncomfortable. Although it isn t possible to diagnose your problem without an examination, it sounds like you have a pilonidal cyst, which is a grape-like pocket in your skin that is composed of epidermal cells, hairs, and debris. Pilonidal cysts nearly always occur at the top of the natal cleft (butt crack), and they often get infected, which leads to swelling, pain and redness. It isn t clear why pilonidal cysts form. It s possible they re the result of loose hairs being forced into the skin by friction and pressure, which triggers an immune response that leads to cyst formation. Another theory is that the cyst forms around the base of a hair follicle that ruptures in the deep layers of skin that is subjected to pressure and shearing forces. In any event, until you see your doctor, apply warm packs to the tender area between your buttocks. Avoid sitting directly on the lump (a donut pillow is often helpful), and take an over-the-counter anti-inflammatory (ibuprofen, naproxen, etc.) or acetaminophen (paracetamol) for the pain. I hope that helps, and good luck!