Are you being regularly examined by your neurologist? Was your original diagnosis relapsing-remitting MS? I ask because you could have transitioned to Secondary-Progressive. As well, having to constantly combat a viral infection that presents itself as effecting the nerves, well I could well imagine that playing a part or at the very least making things more difficult.
Has/have your doctor(s) discussed taking a different approach if your MS has progressed?
this aging question is tough - I'm right there with you in years and have to always stop and ask what is due to my MS and what is age related? I'm sure you find yourself doing the same.
Chronic shingles? Oh my - that is tough since we can't take the vaccine (or shouldn't). Are your flares timed to sort of match those outbreaks? That might be a big clue to share with your neurologist.
Immesceo says it best- talk to your doctor(s) about your disease course and what changes you might make to your current treatment.