Are you short of breath? Are you able to take a deep breath in and out?

That "weight around the waist" feeling could be weak diaphragm muscles. If you're short of breath, I suggest seeing a pulmonologist to be evaluated and have breathing tests (including MIP and MEP).

Are your symptoms worse in the hot weather?

Please do mention the back to your neurologist.

If you get to the point where you can't move or breathe well, you need to go to the ER. If it's bad, dial 911. If you have MG, you can have what's called a myasthenic crisis, which is an emergency.

I hope you'll get answers soon. Waiting sucks, doesn't it?!

Annie