Thanks for both of the responses, I really appreciate the thoroughness both of you employed in your response.
Disregarding my attempt to get "pressure headache" defined, I'll just tell you what my basic symptoms are. The core symptom is just a feeling of pressure in my head, not like there's a tight band around my head, but more of a sensation that things are moving around inside my head and are "clogged." In other words it feels as if something is present inside my head that shouldn't be--perhaps this may be the only way to describe it?
I've just turned 28, my blood pressure is always normal, no diagnosed physical health problems. I've had this "head pressure" for nearly 6 years now. It seems to subside a little through the process of eating, but comes back a lot worse 30-60 minutes after the meal is done. The same phenomenon with exercise: exercise initially reduces it, but then makes it worse. The more rigorous the exercise, the worse the "rebound" effect. Lifting heavy objects seems to make head pressure worse. Lying flat on my back, or in any position, often does nothing for it. Sometimes it's even worse when I'm lying down than when I'm standing up.
It's really killing me because I can't concentrate with it and it seems to cause intense brain fog. Have not seen a neurologist or gotten any scans because I have no insurance.
Lemme know if you can think of anything,