Hi there, I have had a bump under the skin on my "bottom" for a little over six years now. It started out pretty small, a little smaller than a dime and is now about the width of a quarter.It has never hurt or bothered me. Yesterday, I sat on the edge of a chair and I felt a popping sensation under the skin. Since then I have been in a lot of pain. The bump and a pretty good sized area around it feel like it is brused. What could this be? Your answer would be greatly appreciated! Thank you in advance!