Sorry you’ve been struggling with your legs. Things like this really aren’t much fun : (
The first thing to say is, this isn’t a stupid question to ask your MS nurse. Your post makes it sound like because of your age & length of diagnosis, you should be sorted & know everything you need to know, but that’s never really going to be the case for an illness that varies as much as MS does. So you should definitely call your MS nurse, as there are different medications that can help with pain. For restless leg syndrome though, I find taking magnesium pills really good. I take it in the evening or when going to bed whenever I get it, and it quickly sorts it within about half an hour. It needs to be a decent dose of magnesium, roughly 100% of your recommended daily allowance - just a multi-vitamin won’t be strong enough. You’ll be able to get it from somewhere like Holland & Barrett or Boots.
Hope you find the right thing to help quickly!