Update is that pressure is still intermittently there, still doesn't bother me, but most other symptoms have gone away because I am 99% sure I've pinpointed the culprit: to wit, my new MacBook screen.
Roughly, here is how it went:
*bought new Macbook in June
*symptoms began at that time
*worked nonstop on project on the new MacBook through December
*went through all the doctors, MRI, etc. in December
*went back to my old ibook in February because I removed all of its internet capacity (I'm a writer, and the Internet is the ultimate productivity destroyer (for me, at least))
*cessation of symptoms was almost immediate
*activation/provocation of symptoms almost immediate whenever I use the computer I'm on now (the new MacBook, which I use for email)
So I should qualify my initial response to your question: symptoms go away when I am not on this computer, which is now seldom.
I never went over this with doctor so I am self-diagnosing this, so take it for what it's worth, but then again, symptoms don't lie. Still no explanation for my bizarre reaction to the MRI, however.
Food for thought: I've been online, figuratively speaking, since 1996. I have wondered if I might be an example of what's going to happen to us as we all spend more and more time online, staring at screens...long-term effects, etc. Also wonder if it's the nature of the later-model screens, perhaps. I don't know. I can also say that if I look at my new BlackBerry screen in the dark my eyes really don't like it at all. Good luck to you, and hope my observations were of some use.