I've used baclofen for about 10 years and it helps my spasticity immeasureably (sp?).
I asked my doctor for it when I read about it, and I now use about 60 mg. a day, and it does lessen the stiffness of M.S. I couldn't live without it. I've never noticed any side-effects from it. Whenever a person's muscles are stiffened I guess pain can result. Just be sure to ask your doctor for something to lessen your M.S. spasticity. I've never used anything but baclofen, but I'm sure there are other drugs that do the same thing. Baclofen isn't meant to be a pain-reliever, but a spasticity-reliever, which in turn relieves pain.
Good luck with whatever you try.....