Gabe, I am sensitive to your struggle my friend! I must share with you I fought through a very similar battle- for almost 8 years. Attempting any and all remedies possible. Nothing really helped and I was exhaustive in my pursuit (including Butyco). Almost 1 year ago I stumbled upon a method that has GREATLY helped. I am excited to share it with you in hopes you may experience some freedom. It is called the wim hoff method. There is a book by that name. This method is really quite simple , takes some discipline to employ and many are not willing to do that. However, I believe you are one who could. Nothing worthwhile ever comes easy.
I was a police officer under a tremendous amount of stress and had developed a sever case of SOB. This method has provided me with a freedom to breathe that I had only dreamed of. It is not a cure but must become a part of ones life.