What Causes Burning Sensation In Face, Legs And Arms?

I started having burning sensations on my face about 10 years ago and it is now in my feet and hands. It is spreading up my legs and arms. Has not hit the tosro yet. I feel like I have Icy-Hot on my skin. My feet feel cold, even in a hot tub. I've been tested for circulation issues, but all is fine. I don't understand why is is getting progressively worse. I've been tested for MS, too. I really want this to stop. It is very distracting feeling like I'm sunburned all of the time. It does flare up and wane, but it is always with me. Any ideas?