I believe that many answers can be had from examining your lifestyle carefully. What you do, hobbies, what illnesses you've had, vaccines, drugs, antibiotics, solvent exposure and other chemicals, diet..etc.

Keeping a journal may help...if you have good days and worse ones. Once you see what a trigger may have been, you can try the various supplements to help with that particular trigger.

Doctors still do not look for DNA errors... in methylation. (rarely do they test for MTHFR mutations)
They don't understand B6 very well, or B12. They don't understand magnesium at all. They don't understand the effects of LOW blood sugars on nerves. They don't understand high carbs food intake can harm nerves over time esp if you are low in thiamine (B1) or have a genetic problem with thiamine. And they pooh pooh food intolerances. So much of what can be done, is left to the patients to do for themselves, IMO.