Hello! I have had this hard unmovable bump behind my ear for a while now. I would say I first noticed it perhaps 2 years ago. I am 18 now. It is about the size of a marble, well maybe just a tad smaller than that. It doesn't change in size at all. I forget about it, but then every once in a while I rub against it and I begin worrying about what it can be. I am not sure if this is something that some people acquire during puberty or if it is something to worry about. Also, the bump has no odd texture and I never experience any pain with it. Any help would be greatly appreciated!