Have you done any blood pressure checking when you have a head ache ? I think everybody who struggles with head aches should have a home blood pressure kit. Then you can determine if head aches are related to blood pressure. They only cost $30 to $50, depending on features. Avoid the wrist systems if you can afford to. They are not as accurate.

Biofeedback teaches you how to regulate your blood pressure and such. There are neurofeedback systems that teach you how to regulate how your brain functions. It can result in more sustainable results.

Has anybody worked on your neck to see if you have spasming neck muscles ?