you could try asking for a serum magnesium test. the fatigue, depression and muscular tightness, along with the ms diagnosis all point to poor magnesium status (among other things).
if you do manage to get a test, make sure you get your own copy of the results and bring them here. magnesium is one of those things for which the result 'normal' is meaningless. if the results are indeed low and you are able to make the right changes re food intakes and possibly supplements, you could see a big difference.
bahaha world without zinc https://www.youtube.com/watch?v=U1iCZpFMYd0