Multiple Sclerosis involves demyelination, where the malfunctioning immune system attacks insulating nerve tissues, the myelin sheath, allowing nerve impulses along the nerve to leak out. Like removing the insulation on an electrical wire. Nerve signals "short out."
And, yes, this (as with so many other disease processes) is a form of inflammation, where the immune system attacks normal, good body tissues.
MS therapies attempt to turn down the inflammation, turning down the immune system. But with that, infections and other untoward outcomes can proliferate.