Can you specify when your "brain quakes" were happening.
Was it when you turned your head?
I am sure you looked up MS which is why you were thinking that you had it, as there is a sign "Lhermitte's sign", however, you can also get that in b-12 defeciency and other things.

Did they do an LP?

*I'm a frequent chatter at an MS chat, as I had no clue what was wrong with me in the initial stages of testing, and someone had suggested MS*

I hope the figure it out.