hi Stephen, as you said, you need MRI's of upper spine. it could be so many things but you need a lot more diagnosing done instead of just PT. sure sounds like nerve impingement or disc/spine issues with the going numb and cold issues. The mental status and speech changes are certainly frightening too....I would ask doc for brain MRI as well.

You said you are not sleeping and that only makes matters worse. Are you taking anything to help you sleep? I know when I first started with pain mgmt and I never slept, my doc gave me Elavil and it knocked me out and I was able to sleep. Even though it is technically a anti-d, it is used for pain and sleep. Have you tried meds for nerve pain?

You have my sympathy, it is so scary and frustrating when you know something is going on and the reason cannot be found. I would advise not sticking with just one doc like a primary care or physiotherapist...seek out various doctors like a pain mgmt doctor or neurologist.
take care, Diandra