Everything that you have written, I have/had experienced. The only difference is....I had the neuroma surgery. I can only say that the zaps have stopped, but I have to come to grips with the residual numbness in my feet. The sock balled up feeling is exactly how my feet felt when it started. I had the EMG plus the skin biopsy. All were negative. I would agree with the MRI testing and I would also get additional blood work done to rule out MGUS. It is a blood disorder that has peripheral neuropathy as a side effect. I also had the back injections...I have the same disk issues as you. Nerve disorders are a strange breed of problems. As many in here know....I've done it all. All you can do is keep on working with your doctors. Find a neurologist that you can trust and are comfortable with.