Hi, I'm an 18 year old female and over the past month or two I have noticed a hard lump on my tailbone. It is about the size of a dime and is firm. It does not move around and there is no irritation or pain around the area. You would not know it was there by just looking at it, you have to push down on it to feel it. I've read about having a cyst in this area, but I do not think this is the case due to there being no skin irritation/redness/drainage and no pain. If it is not a cyst, then what could it be?