I agree with everyone's posts on detoxing. For most Lyme patients, toxins are the cause of headaches.
I get occassional headaches like you describe (not 24/7), but mine are more the result of having been in a car accident where the neck and the plates of the skull were affected. Because I had skull plates slightly out of place, they would press on things, and I would get terrible pain behind the right eye, going through the forehead, around the top of the skull, and into the right jaw joint and neck. A combination of chiropractic and craniosacral therapy is finally helping correct this, after seven years. I also have a mouth guard for TMJ and teeth grinding, which helps stabilize the jaw joints.