This "pressure in your head" thing is being reported more and more often on health forums, a good and bad thing. Good because it means those that suffer from it, myself included, aren't alone and maybe can help each other. Bad because it really sucks to have it, especially the 24/7 variety.
I've had it 24/7 for 7 years. Thankfully I do not have actual migraine attacks with it, I only get "typical headaches" once in a while. I have some other strange symptoms, but generally it's just the pressure that I deal with. Relative to other reports on this site, I would rate it at "medium" intensity. It does not impede my ability to function, only hinders me in certain ways and it's a major irritant.
I finally decided to do something about it, got tested, saw the neuro, and I'm supposed to take 100mg of Topamax daily. I'm up to 50mg daily and no relief so far, but we'll see.