Angell,

If the pain is sufficient that you require Hydrocodone, then it seems possible that there is something else apart from or alongside the MG going wrong.

Also if Hydrocodone is "fixing" all the problems, even, temporarily, that does not sound like MG. It is not uncommon for people with one autoimmune disease to acquire a 2nd one, after all the problem is the autoimmune system, MG or Lupus or whatever is simply the manner in which your autoimmune system has decided to malfunction.