@deanbiglets
Hi Dean, welcome to Connect! You are the second one that I know of who said their peripheral neuropathy (PN) was caused by a low b12 level. Another member, @rwinney also developed near crippling neuropathy in many parts of her body (feet included) and is totally convinced ( as was her doctor) that low b12 put her in that condition. I have confirmed through some online research whereby other websites mention b12 as a possible cause of PN, so obviously a number of people are in that category. As far as the muscle issues you are experiencing, I do know that quite a few people here swear by Myofascial release, have you heard of it? There is a discussion here that addresses it that you might look at:
https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/
This might be helpful to you, for both your feet and you knee issues.

Regarding medications, there seems to be a pattern I have noticed that physicians rely on which include gabapentin, Lyrica (pregabalin) and Cymbalta (duloxetine). Some people are helped by one of these, many are not. Many people after trying these unsuccessfully (like my wife) move on to a variety of relaxants and stimulants such as THC based marijuana or cannabis oil as well as kratom, ketamine, etc. You may eventually decided to explore one of these if you find nothing else for relief of your pain. I do hope you are able to find a way to cope with your pain so you can continue to lead a normal life. Unfortunately, my wife's PN in her feet/ankles (since 2014 from chemo) has reduced her world considerably, a very sad state of affairs. Best, Hank