I too have constant headaches. My neuro asked me several times, when do they start, when do they stop? I told him, I go to bed with them, I wake up with them, to let me know if he could figure out when they start and stop. He has finally quit asking me that question.
He wants me to try accupuncture and see if that might help. We tried Topamax, anxiety meds, PT, I lost weight, changed my eating habits, which in my mind means it's not food. We have decided they are from my stress and the muscles in my neck.
I was reading about headaches the other day and it said that many people actually have migraines thinking it's just a sinus headache. It all made sense to me even though I always thought migraines were always so bad all you could do was lay in a dark room.