Non-injury painful lump on back of head?

I have a history of headaches and migraines, this is much different. The pain and lump started Thurs, and pain the is very localized. The pain and lump are about 1/2 inch behind my right ear and a 1/4 to 1/2 and inch above my hair line. I went to the doctor Friday and was sent to the ER because my GP didn't know what was wrong. At the ER they did a CT scan of my head and C-spine and XRays of my C-spine, all were clear. So they gave me a shot of morphine for pain and phenergan for nausea. I got discharged with a "spranged neck" and some pain meds. My neck doesn't hurt. No neuro test were done, I'm still in pain and now it's getting worse and spreading to the entire right hemisphere. What is this???