Ann, i certainly could not say if my sensitivity to chemicals (signaled by their smells in some cases) is due to MS in any part. I know people with Porphyria have this. It is a good question to which I have NO answer.
Some people are just plain "chemically sensitive" without any other dx attached to it, and this can be very severe. I get the newsletter of the Chemically Injured Information Network, "Our Toxic Times." Many there are more sensitive than I am.
I have all sorts of inconvenient chem sensitivities. One is to printer's ink. I cannot take a newspaper subscription because they roll the papers up soon after producing them. I can buy a paper from a news stand because they are laid flat and consequently outgas.

my father suffered all of his life from Porphyria, and he worked in a newspaper office that was horribly smelly. I used to visit him there often. he had no idea what the chemicals were doing to him, but he knew that the flourescent lights got to him. So when the newspaper moved to a new building, he had his department designed without flourescent lights. Driving by the newspaper, even after he was gone, I would look up at one corner of the building which had incandescent lights, and think of him.