i think getting assessed for lyme would be a good idea, and if you want to rule out nutrient issues, get all those things tested and don't accept anyone telling you your levels are 'normal'. read that nutrition first link below if you need clarification on what 'normal' actually means wrt blood testing.
sorry i can't help you re a good doc for a second opinion :S
all i know is that one of the big guns (m.f.holick) on vit d3 research as it pertains to various illnesses, including ms, works there.. http://www.bumc.bu.edu/endo/faculty/holick/
welcome to the forum - lots of support here! any questions re nutrition, feel free to ask