This is not the sort of thing you Google. IF a child won't let you touch him, he's either having a tantrum, faking, or in need of medical attention. If you rule out 1 and 2, your only option is 3. A child just can't be allowed to decide if a parent can check his feet (or other body part) or not. If you can't solve a problem immediately with something like ice or heat, you go to the pediatrician, not to Dr. Google. Yes, you might need a neurologist or a podiatrist, but you start with the pedi so there is a referral and so the child's existing record follows you to the specialist. But searching on line for sources of this kind of neuropathy doesn't help you and it just wastes time.
Since this pain is intermittent and unexpected, I'd consider having your phone ready to video him in the throes of this pain so the doctor can see the child's behavior. I'd also keep a journal for when it started, how long it lasted, and what he was doing just before and just afterwards.
And I'd call in to the doctor instead of waiting for the regular check-up to see if they want you to come in sooner. A child who is screaming and unable to walk deserves more than a "mention" when you go in for a check-up sometime down the line. If he's faking, then taking it seriously will take care of it. IF it's real, then you teach your child to come to you with these problems and show him you will address them.