I am having this really weird and scary problem.

I feel this strange sensation-almost like a tension headache-when I pressed mildly hard on the back of my head.

Its not tender to the touch but I really have to massage the area. I feel the same exact feeling one feels during a tension headache around my eyes and temple.

A) What could be causing this?
B) Is it a muscular problem or something with the brain?

Please help!