I've had this issue before. About 4 years ago I felt the lower back of my skull for no reason. And felt a bump I felt the other side and it did feel the same but it wasn't as large as the other side...so I started to freak out about it and I would constantly check it over and over again. I would be able to convince myself and realize it was just the shape of my skull. It did feel hard like bone. I was able to get over that but now it came back and I have the same fear. I'm also constantly checking and I'm either convinced that it's my skull or I would think it's a tumor. I guess my issue is the constant checking and fear of a brain tumor. I also have all these weird aches in my head which isn't helping. Deep down I know it's nothing....but there's s part of me that just can't let go of all the worrying. Does anyone else have an different shaped skull? And how would a tumor feel like on my head? Can anyone comfort me on this? I just need a little convincing.