My symptoms are burning pain from the waist down all the way to my feet that is worse when lying down and better when standing. i also get very bad muscle cramping all over my body from my neck down to my feet. can this be small fiber neuropathy?

There are many types of neuropathy-small fiber being one of them. Your symptoms could certainly be due to a neuropathy of some type. You should see a neurologist for evaluation-you will need to be examined and then testing done to determine the etiology of your symptoms. There is treatment depending on the exact diagnosis. So, see a neurologist for diagnosis/treatment. Good luck!

Peripheral neuropathy, especially involving the small fibers is one possibility, but a problem over the lower spinal cord or within the lumbosacral cistern, such as spinal stenosis, might be another explanation. See a neurologist and get this evaluated fully.