It's great to talk with you. The great thing I have found about this forum compared to some others I have visited, is that people don't on the whole try to act like doctors. Anyone with any experience of MS or any other neuro disease, will readily admit that no two cases are the same, and while certain symptoms may seem similar, others may be totally different.
If you were to take two people, both with PPMS for example, their stories would be similar in places, but totally different in others - it's best left to the experts surely, even if many of us don't have much faith in some of their decisions. The tests they run are the best available at the current time.
On the left sided weakness thing, I'm a contradiction to that one straight away. Perhaps I'm in the minority but most of my weakness started on the right side, but after eleven years has now evened itself out
I'm sorry not to have been more help, but that's the way I see it. I hope the medics manage to sort you out in the not too distant future.
All the very best,