I have a lump behind my ear on the bone

[Nickk_]

I'm 16 years old and I have a lump right behind my ear on the bone i think I've had it for a while maybe a year or more I barely noticed it the other day when I was rubbing behind my ear it's hard maybe a little bit squishy I don't know what it is and it causes me extreme anxiety not knowing what it is could it be something very bad or something harmless I don't feel sick I don't have headaches I don't feel tired I feel fine it doesn't hurt when I touch it and it moves a little bit it's the size of an eraser on a pencil could it be because I got punched in the area about a year ago? I also have a lump on my lower back on the right side with the same description I went to the doctors and they said it's nothing they wanted to do an ultra sound before taking it out but I was too scared to go please help I have extremely bad anxiety and it causes me to have panic attacks constantly during the day I appreciate any help thank you