I work in IT as well and experience the same problem with "computer headaches" as you. Pressure and tension starting in my right temple and can get pretty bad if I don't back off in time. They can last for up to 5 hours I've noticed. Mine started about a month into my PCS(7 months now). At first, I tried different refresh rates, dimming the contrast/brightness, and even tried Gunnar glasses. Nothing worked very..very frustrating.

It wasn't until I started taking Amitriptyline that the headaches became more manageable. Provided I get good quality REM sleep the night before which can still be a challenge, my headaches are now limited to end of the day. Some days, usually if I leave early and have low stress, I can escape without one. When I get home I try to stay away from the computer as much as possible(being on-call sucks!). I still dim my monitors quite a bit, take frequent breaks(about 1 or 2 an hour), and take a 20-30 minute walk during my lunch break. Also, f.lux works pretty well to alter the colors to darker comfortable level. Good on Windows, doesn't work on Ubuntu http://stereopsis.com/flux/ (Giving a holla, to MrSmith1984 for this one, thanks Dude!)

Your Neurologist should be able to prescribe you Amitriptyline or something similar to help with this. He says the Amitriptyline helps with sleep and the more the quality sleep you get the less likely you are to get these headaches. So it's not the monitor, it's stress level and lack of good sleep. Amitriptyline is not without it's difficulties and side effects(I just started a new thread about my issues with it), but overall works for me.

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7 months PCS. Headaches, tinnitus, anxiety, depression, easily aggravated. Did this to myself. One too many bourbon shots. Did a face plant on the sidewalk. Sustained concussions from this(embarassed) before, but first time from PCS. Been alcohol-free since this happened, found Jesus, and have done a personal and spiritual 180.