I know it is frustrating trying to find a correct diagnosis.
I went to four pulmanologist before I finally got diagnosed with asthma. It took the methacoline challenge test to be positive about the diagnosis. Most doctors wouldn't consider I had asthma because I never wheeze. They blamed in on cardiac problems and everything else. I finally found my last doctor who did the methacoline challenge test because he said my cardiologist was positive from all the testing I had done that it wasn't cardiac and some of the symptoms sounded like asthma. It turns out I have severe asthma that went undiagnosed for many years. If you take the test and it comes back positive I would try the asthma medicines and see if they help. If they don't I would go to a large city with specialists and get a second opinion. sometimes it takes a large number of doctors to find one to diagnose you.