This is an interesting thread. There are a couple of points to make.

1. Any doctor who cannot tell the difference between a "stress" (read tension) headache and a sinus/migraine/cluster headache needs to go back over his old medical school notes. Tension headaches are the easiest to diagnose (and, BTW, the hardest to effectively treat).

2. While textbooks try to categorize headaches (migraine, cluster, trauma, tension, etc.) a specialist with experience will tell you that there are so many variations on these themes that many headaches are not classifiable (like mine, see some of my earlier posts, especially my 100th).

3. Find a headache specialist. PCP's are not going to be able to help anyone unless they have "classic" symptoms. Even a good neurologist will most likely not be up to it. Believe me, I live in a major metropolitan area, and the # 1 neurologist in the area punted on me and handed me off to a headache specialist-- who saved my you know what.
D.