Hi ~ It sounds like you have neuropathy in the feet. It would PROBABLY be caused by the spine. What you describe sounds like nerve damage.
Have you had an MRI in the last year? If not, I'd ask for a new one with and without contrast material. Then after you have this done, take it to a spine specialist -- a neurosurgeon or orthopedic surgeon. I'm not advocating surgery, but you at least need an opinion.
There are antiseizure drugs that take care of nerve pain/neuropathy. These meds were found to stop the burning/stinging/pain of neuropathy. A couple of these meds are Neurontin (Gabapentin) or Topamax. Ask your doctor about possibly putting you on one of these meds.
I wish you the very best -- keep us posted on how you're doing. God bless. Hugs, Lee