You said you've been to a Neurologist, but have you been to a Neurosurgeon? These are two quite different doctors. You might try a Neurosurgeon -- he might have a better idea of what's going on.
Other than that, you've covered it quite well !

Can you go to a DIFFERENT pain management doctor? The one you went to sounds like a joke to me. He didn't sound very concerned if you ask me. I would hope you could find one that would work harder at finding the cause of this problem! The one I went to worked diligently at trying to find the reason for my pain -- unfortunately, he wasn't able to.
Anyway - Hopefully if you haven't seen a Neurosurgeon, he'll be able to help you. Maybe between him and another pain doc, they'll be able to help you! I certainly hope so. God bless and please keep in touch. I'd really like to know the outcome! Take care. Hugs, Lee