Sounds like a cyst.If you have your ears pierced, this is probably the case. I get these often because I wear wooden earrings. If it's a really big bump, more on your neck region, go to the doctor.
Try putting a glob of antibiotic polysporin on it a few times a day and see if it goes away. Clean your earrings more often or switch to an expensive metal like gold or silver, or switch to surgical steel.
Go get it checked. could be a swoolen lymph node.