Alot is unknown about PN. This why you are HERE, and why your doctor is not helping you.

Your lab range for B12 is the outdated old one, where lows are
in the 200 range and called "normal". This is unacceptable.

We have tons of information gathered here on the Subforum and on the B12 thread and some at the vitamin forum.

To start you need to up your B12 to a level at least of 1000.
Use Methylcobalamin 5mg orally on an empty stomach, for about 3 months and get retested.

Start the magnesium, and with both of those see how things go.

Avoid sugar, MSG, and gluten if possible. There are over 100 types of PN, and you have to approach this carefully and with thought.

You could have a hereditary CMT. At this point you just don't know. Try to relax, do meditation exercises, and keep your brain off your discomforts. If you focus on them they will burn a pathway to your pain centers and become self perpetuating.
This is the new way to approach chronic pain. Do not allow your brain to train itself to focus on discomforts. You can Google and find these techniques, for many types of pain.