How Can Severe Headaches Be Treated?

My husband has been having intermittent HA more nerve pain like for a year. He has gone to an ENT. Normal CT Sinus & MRI/MRA Brain. His pain is in the R temporal & R Frontal area. He did have a root canal on an upper molar last year. He is having actual severe pain episodes so it is disheartening for everything so far to be normal although that is good news. When he has the HAs he seems to rub the area with slight relief.