There are some symptoms of MS that can cause breathing problems and meds as well. I do agree with Gretchen that a call to the doctor is warranted to figure out what is causing it and what you should do. My husband for example, has breathing problems in two cases. One is a post injection reaction from Copaxone, very rarely, but it has happened, and the other from the MS hug which makes him feel like he can't get in enough air.
Here is an article that might interest you and others on the topic. Please let us know if you find out anything.
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