Constant headache and pressure; thyroid related?

I've had really intense pressure, where it feels like my skull is too small for my brain (not likely!), for 10 months. It began with a very salt & msg-laden meal on 11/26/2009. This has happened before--where I get a terrible headache & feeling of incredible pressure with salty meals, and am very thirsty, but before now it has always gone away.

I've had a catscan and MRI that showed no abnormalities; also two recent thyroid tests that appeared normal. However, I do have a multinodular goiter and am wondering if this is causing the headaches and/or pressure. As yet, I haven't had any of the more specific or elaborate thyroid tests, such as TSH antibodies.

Twintwo, who posted back in March of 2008, was describing symptoms a lot like mine. I would be interested to know if she found some relief. And, of course, any other help is greatly appreciated.