I discovered a cyst tonight that appeared out of nowhere behind my right ear right before the hair line starts. I'm trying to find out if it is something serious or if I'm worried for nothing. I'm just concerned because I was born with a cyst behind the same ear and it had to be surgically removed. At the current moment it doesn't hurt and it's about the size of a small peanut. Does anyone know what this is? Should I even be concerned?

You should be worried for something and seek out the examination and advice of a medical doctor at your earliest convenience.

The best thing that you can do is to go to a medical doctor to have your questions answered, and thus worries and fears relieved, as to whether it is serious or not.

On this site, we can give you advice as to what it might be, but you would receive the same kind of information if you were to read a book on medical symptoms. We aren't a substitute for a medical doctor's physical examination of you.

If you want to quit worrying about it rather than keep researching it on your own or with the aid of others who are on a site such as this, then please get to a medical doctor who can examine you in person.