Certainly, chemotherapy can cause neuropathy--and it doesn't always improve markedly once the therapy regimen ceases. B12 deficiency can cause neuropathy (and I imagine if you have had B12 problems, having cancer and chemo would have exacerbated them--and you will probably need to supplement for life, and not just with periodic injections, but orally and every day). Cancer itself can cause neuropathy, and that also doesn't always go away entirely post-remission/control, especially with the blood cancers, as the rogue antibodies manufactured in many of these seem to cross react with many components of peripheral nerve, and the antibody titers may linger . . .

Sounds like you need a very comprehensive work-up from a neuropathy specialty practice, and to have such a place take all of this history in account for testing.