Today while at work in my office I got a sudden pain on the back of my head, at the base of my cranium where it meets the left neck muscle. I reached up and noticed a lump the size of a small marble there, tender to the touch. It was not there this morning when I brushed my hair. The pain worsened slightly but steadily for a few hours, and radiated through my neck, left ear, and head. Now, about six hours later, if feels slightly better, but still the lump is tender. Otherwise, I feel fine. I have not ailments and no diseases. I m a 50 year old woman.