Hi, my name is Hank, and I'd also like to welcome you to this forum. I have read what you wrote. So the EMG shows diffuse myotonia? If the genetic test shows it as well (I hope not!) you will have one diagnosis that will account for some of your problems. There is another person on here who has myotonia congenita, @kimcvi whom you can contact to exchange notes. There is a discussion which she started about her MC. Here is the link: https://connect.mayoclinic.org/discussion/myotonia-congenita/?pg=6#comment-418222
The thing I remember most about her was her frustration with not being able to share or network with others with MC since it's so rare.
Not sure whether you know how to get around on Connect, but if you click on any Mayo name (in blue, with the "@" symbol) you will be taken to their profile which contains a history of all of that person's posts, which is very useful for learning about their story as they have discussed it on Connect. It sounds like your sensory symptoms resemble peripheral neuropathy. There is an entire group on connect regarding neuropathy, just FYI.
Some people present with a wide array of symptoms affecting different locations of the body and different systems. Because you were otherwise healthy prior to your medial left foot issue in 2016 it may be that everything has proceeded from one main cause, whatever it may be, and it might just be genetic in origin. One thing's for sure, rule everything in, and read as much as you can about different symptoms and diseases, both here on Connect and on the broader internet. A couple of recent examples of youngish people with a broad array of symptoms here on Connect:
-yesterday a young (27) lady @hypotemusea wondered whether her symptoms might stem from contracting Lyme disease. You could ask yourself if this is likely in your case.
-a while back a woman of 42 @brayimee also had a compendium of seemingly unrelated and dispersed symptoms. So far she has been treated for Slipping Rib syndrome which her doctor believes may be at the root of all/most of her issues (she was operated on for that a couple of months ago). Some of her symptoms are still with her.
Right now you are in the mystery stage, an uncomfortable place to be as you try to live your life with a variety of inconvenient and very painful issues without explanation. As I said earlier, please be open to all info that comes your way, be one pointed in your efforts to get to the bottom of this, and hopefully one day soon you will have some sort of answer(s). Advocate for yourself and become a motivated researcher. I have been amazed where doing that can lead. Something is out there for you to find that can help, and you may very well find it if you put enough effort in. Sorry for just a pep talk, it's about all I can do here, but I think it is good advice for you.
Meanwhile, though I do understand the need for things to deal with pain, be careful about the drugs they suggest. Really understand both short term and long term side effects. Consider alternatives. One is low dose naltrexone (LDN) which you can find out about through internet search (and there is a Connect discussion about that also). Connect is a great pace to canoodle ideas with other people. Good luck and will hope to learn more about your ailments as you do. Keep us updated if you would. Thanks.