I hate to ask such a bazaar question, but I've been diagnosed with SFN, no biopsy, but based on symptoms. Large fiber and muscles okay. When. I go the bathroom, doesn't matter which, both my feet begin to burn and then as I go, the burning gets less and once I'm done, the burning in my feet are gone. If I stand in same position or sit in same position, no burning, only when I'm using restroom. Anyone have an idea? Is this something totally separate of SFN? People think I'm nuts, but it happens every time.