Just a couple of thoughts I had

While I bet the protonix and the nexium type products help gerd they maybe reducing some of the enzymes or acid needed for absorption of B12 among other things. So you could be malabsorbing nutrients and supplementing might very well be a good idea.

Something that went hand in hand for me when it came ot the malabsorption was iron. Like B12 which is a big molecule and hard to absorp i also was iron deficient anemic. And iron deficiency can also cause neuropathy type symptoms. But do not mess with iron unless a doc tests you for it although a daily vitamin with some iron in it probably would not hurt you. You can ask for a total iron, total iron binding capacity and ferritin test.

And just because we are on deficiencies you should also test your vitamin d as well. There is a great deal of evidence that there is a good deal of D Deficiency in the US and this can cause muslce pain and weakness.