What vitamins in a persons body can affect breathing.muscles if calcium and magnesium are good but have elevated parathyroid hormone?

Whoa: Your breathing muscles need no special vitamins beyond what you'll get with a halfway reasonable diet. What concerns me is your having an elevated parathyroid hormone. Either you have a parathyroid adenoma / hyperplasia which is really serious, or you are vitamin d deficient. You need to address this. You'll feel much better. Again, please forgive my frankness & do right by yourself.