You should call your doctor right away and tell him about the breathing issue. If you define it as "serious breathing difficulties" you should go right to ER. Things can quickly turn for the worse.

Let me guess. The symptoms are more pronounced late in the day and late into the week. Sometime it is OK. These are classic MG symptoms. They were the first ones that I experienced.

Have you noticed any weakens in the jaw when eating? It would feel like your mouth is tired. It is subtle at first, and it is sporadic. Later you ask yourself why is it taking 10 minutes to eat this McDonald's Fish Sandwich? This is the first time I knew something was really wrong, about 3 months before my first MG crises in September 2013.

I asked my first neurologist what they do in the situation of obvious MG symptoms, but a negative blood test. He said it involved complicated test designed to fatigue the muscles.

I responded asking why not just give a few doses of Mestinon, and see if that tamps back the symptoms. He just said something like we do not work that way.

Then I though about Theodoric of York: "the medieval barber gives medical treatments and fine haircuts."

https://screen.yahoo.com/medieval-barber-000000006.html

I was lucky to have a positive blood.

Good luck,

-Mark-