Once again, burning nerve pain IS NOT a part of ANY motor neuron disease! Burning nerve pain is associated with peripheral sensory nerves. It is most often associated with peripheral neuropathy, which can occur for a bunch of reasons and sometimes it's idiopathic (that is, they have no idea why it happens) . . . but can be associated with peripheral diseases such as CIDP or Guillian Barre for example.
Again, if you or anyone else has burning nerve pain, you do not have a motor neuron disease. As I also said before, you can feel burning nerve pain later on in the course of a motor neuron disease due to edema for example, but that is a secondary affect.