Hi jon mark, I'm surprised no one has jumped in on this one yet. In all honesty, from everything I have seen and heard, I'm not sure normal EMG/NCS results by themselves will 100% rule out anything out, its just a piece of the diagnostic puzzle. However, those tests are generally looking at large nerve fibers that control muscles, so normal results tend to point away from motor neuron diseases, or other large fiber injuries or neuropathies (ie: things that affect your muscle strength). They generally do not tell you much about small fiber neuropathies (ierimarily things that affect your sense of touch, or autonomic function).

Since you are experiencing widespread burning sensations which are more typical of small fiber neuropathies, the skin biopsy is the route to go from a diagnosic standpoint. But for some reason, doctors do tend to be hesitant to order that test.