If your doctor is up for it, or you can find a doctor that is, try Oxycodone. It's the generic of Oxycontin. It can be found in 30mg tablets that are instant release, and costs much less than Oxycontin. They can be cut in quarters. There is a nation-wide shortage right now and I can only get the 30s. I cut them in half.Yes, it is habit forming for some people, but not everyone. I have very similar pain, and so far it is the only thing that helps that doesn't make me throw up.
For your tight muscles, try Flexeril. It is a muscle relaxer that doesn't make you sleepy. (I use Xanax for sleep and the occasional anxiety attack).
Did you get a second opinion? MS seems so easy a diagnosis. I looked it up in my Merck Manual and there are a few symptoms that I lack for a complete diagnosis.
And, as you pointed out, the doctors are in a big rush to get you out of there, so it's hard to find the right thing.
(Pardon me, all you doctors reading this. I have just had one bad experience after another and that only adds to the misery).
I wish you well. I will post more as I learn.
Aurelia5