There Is A Spot On My Head, About Dime Size,

There is a spot on my head, about dime size, located about 3" behind my ear, and a little higher. It has been very sore to the touch (no recent or past trauma), and about 2 weeks ago I started to have daily headaches emanating from the sore spot. There's nothing on my scalp, it feels like a bruise, and for a while that's what I thought it was. But it wouldn't last 2+ months and start headaches even later, I don't think. Thanks for your help.