Knot on head frequent headaches

In April 2007 I was in a bad car wreck and hit my head very hard. I was taken to the doctor 5 hours after the wreck and the doctor said I had a mild concussion. I had a big knot on my head too. A few months later I had to go back to a doctor because of migraines and forgetfulness and they said I had post concussive syndrome. It went away after several months but I still have a rather large knot (like half of a big marble) on the side of my head. I haven’t had a migraine since last December, but I now get frequent headaches (sometimes daily). Before I wrecked my car I maybe had a headache once or twice a year. I told a doctor that sometimes when i lay on the side of my head down with the knot it seemed to trigger headaches. The doctor told me that was not possible. Is it normal to have a Knot on the skull for over 3 years, and could this be causing my head aches?

I had MRI and CT scans 8 months after the wreck and they said it was a hematoma