Hi, I have just discovered a hard lump on the back of my head whilst doing my hair. I have not styled my hair for awhile, just been putting it up, so have not touched the back of my head for awhile. It is a hard lump, feels like bone, the skin moves over it easily. When I press on it I get a dizzying feeling and a slight headache . Should I be going to my doctor to get this checked? or is it my skull changing?