I have a bump behind my ear between my skull and my earlobe on my right side. It is about the size of my fingertip, and it is sore, especially if I touch it in any way. I also have one on my left side, but in front, just below, and slightly forward from the area where someone would get a tragus piercing. (Here is a guide ear piercings for clarification: WWW.WWWW.WW That bump is much smaller and firm, more akin to the size of a ball on the end of a pin. It isn t sore, either, unless I put a fair amount of pressure on it. I periodically get these bumps, and then they go away after some time--I am never sure when, I just wake up one day and realize that they are gone, and I can t remember when it happened. Sometimes they shrink instead. I usually have two or three behind my earlobe on my right side, but they are usually much more firm than the large one that is currently residing there, and they usually don t hurt the way this larger one does. I have gotten this exact same kind of bumps before, as I have said, and they hurt, as I had previously assumed, because there was pressure underneath the skin . After doing some amateur research, I worry that perhaps that is not the only cause.