I can bring a headache on if I get on the computer when I am a bit tired (straight after waking up usually).
I have two types of headaches.
1. The paracetamol headache. This headache is the most common one I think most people experience. I can tell if its one of these types by shaking my head. If it hurts all over, its one of these. It "usually" goes away with a couple of Panadol.
Usually its a result from a big night before or flu.
2. The asprin (migraine) headache. This feels just like the above type headache when still, but if I shake my head, it doesn't make it any worse. If I jump up and down however, I can feel the area in my head quite precisely. I don't know why this is. It usually is in a different spot each time I get one of these. It also usually hurts above my eyes when I roll them around and can make me a little dizzy. Usually only asprin or other type of anti-inflammatory drug will get rid of these nasties.
This is usually brought on by sitting too long on a computer combined with poor sleep and not drinking enough water.
But also, my vertebrae plays a big role in my headaches. Bad posture which is a result of the poor sleep and the sitting on a computer too long. I found treatment from a chiropractor (even just a home massage from the wife) eased the headaches almost immediately. There is a lot to be said about that.
SO what to do? Well I recently quit my office job mainly because of this. I am now in a more physical job which doesn't require me to be on a computer in a (supposedly) ergonomic chair all day. I still get headaches now and then but I feel much better for the change.
Hope this helps!
Alan