Hi I have a bump on the back left side of my head, a little above my hairline, i do not know where it came from because I haven t bumped my head and I m 100% positive of that. It doesn t hurt until I press it, or lay my head down on something. I went swimming a few days ago, and that night I discovered this bump. while I was swimming, I dove under and (the pool is 10 foot deep) my ears both popped. I was thinking I could ve let water in and now I have an inflamed muscle. But I figured it would ve been gone by now, I ve had it for 4 days now and it hasn t went down or stopped hurting. I do not have swimmers ear or a cold . What could this be? Pleaseeeeee help!