I have a lump on my left butt cheek and its very painful and sore could this be a boil ? or something ?

Yes: This is a common area where bug bites or hair follicles may become breeding grounds for staph or other germs that will form an abscess. If you can sit on a heating pad for an extended period or over several hours you may get it to raise to the skin and drain.If not, it may need to be drained by your doc.

Painful Lesion: A painful butt lesion could be: a ruptured epidermoid cyst, a boil, cystic acne, a pilonidal cyst, an infection like bacteria or yeast, a leiomyoma, an eccrine spiradenoma, neuroma, dermatofibroma, angiolipoma, neurilemmoma, endometrioma, glomus tumor, and a granular cell tumor.