Hi and Welcome!

Sorry to hear that things are going wonky for ya. It can be scary.

MS is generally a diagnosis via exculsion since there's a lot of things out there that can mimic it. The follow up MRI would be a start to see if anything has changed. There's a lot of bloodwork to rule stuff like Lyme's out and possibly an LP (spinal tap - though that's being used less). Evoked potentials is another tool that they use as well.

McDonald's Critera is the usual rule of thumb for the docs to DX MS

I had tremors on my right side that lead to my eventual DX. It was scary and annoying to not have control of the bod. I've been fortunate in that it's been the only symptom to fully remit for me.

Hang in there, and hope the docs can find the answer for ya.