Have had the same headache for going on four years now. When it first started I was working at a daycare and assumed it was stress related, but I haven't worked there for over two years.
I wake with it every morning, and it never goes away. I take pain medication like crazy and it has very little effect. The pain is throughout my forehead and behind my eyes. I would describe the pain as "pressure." Pushing up against my eyes or "crunching" my forehead relieves the pressure... for a moment.
In the last year I've had two CT scans, an MRI, an eye exam, done two sleep studies, seen an ENT, Neurologist, had a routine physical... no one can come up with anything. My scans show nothing... no tumors or other red flags. I haven't been to an ENT for close to a year now but at the time he said it was NOT sinus related.
One of the biggest quirks I've noticed is that cold air SEVERELY reduces the pressure, and the opposite is true as well... warm air INTENSIFIES the pressure. I sleep with a fan blowing on me, I have the air conditioner on in my car during the winter. Stepping outside on my breaks and lunches makes almost an immediate improvement... until I go back inside.
Any chance this is ringing a bell for anyone? I've essentially had a headache for four years now, and I'm tired of spending all my time and money to hear doctors tell me, "I dunno what's wrong with you... go see this guy."