I think that we had a thread about this a while ago.... it seems that things get worse as the day goes on for lots of people.... I know that I'll get headaches, drowsy, crappy feeling some afternoons. My headaches start off in the rear- base of the neck area, but they feel like they go straight to the back of my eye.
Billy - allergies may be contributing.... did you tell your doc about the darvocet and how they make you feel?

Also- I had some stretches for my neck and scalene muscles that seem to help alot, since for me those are the muscles that get reaaal itight and lead to headaches.