K9Lover, I am not sure MS has an association with MGUS. I am unaware of having symptoms with MGUS, but then I do have other diseases which give me spasms and spasticity. So it would be hard to discern if any of these came from MGUS. It may be that they do, and I am not aware of it, because I've not paid much attention to MGUS in myself.
If it is in the early stages with low counts, in your tests, I hazard a guess that it is not producing your spasticity. But I plead ignorance.