Hi Whitecap - welcome to the forum

My neuro had me go with sublingual B12 every day for maintenance (2500 mcg). Make sure you use the methyl - not the cyano - compound. Better uptake in the body.

Have you considered seeing another neuro for a second opinion? Many of us have had to get numerous opinions from various specialists before arriving at a dx (and unfortuantely some are still searching).

The most frequent other specialties considered / consulted are rheumatology. endocrinology, and pulmonology.

Perhaps you might wish to consider a pulmonologist first. Muscles need oxygen - and if you are not exchanging oxygen efficiently - then you might experience muscle issues as well as the shortness of breath.

Just a thought. Good luck in your search.