Hi Brian :)
This sounds very similar to me! I spend a great deal of time in front of my pc and have often been told that this could be the cause of my headaches. I know this not to be true though because I can sometimes go up to two weeks with no headache at all and spend just as much time in front of my pc as before!! Am not saying that is the case for you though, maybe try to spend a few days away from your pc (hard I know!) and see how you feel. I've been on holiday in the past where I have been nowhere near a pc screen for two weeks and had nothing but migraine after migraine.
As for the diet I am currently taking daily supplements of magnesium and vitamin b and also iron supplements. I started this around 3 weeks ago and so far have only had 1 full blown migraine attack and much less of my daily tension headaches. I was going to make a post about this in the next few days but am scared to jinx it!!!Before I was having 3 full migraine attacks a week that I would treat with triptans and DAILY tension type headaches.
I was also feeling tired all the time and waking up almost every morning with a headache.
Hope this helps :)