Hi There, I’m 24 Years Old (no Smoker & Bmi

Hi there, I’m 24 years old (no smoker & bmi Of 18.8) with shortness of breath at rest (usually improved with exercises) and Nostril Flaring literally 24/7. I also have a dry cough. I’ve been to my GP who couldn’t hear anything wrong during physical exam, so thought it could be asthma but when I use he inhaler it doesn’t really do any thing. I get very bad anxiety so thought it could be that, but have worked around fumes in a kitchen for past 6 years so worried that may have had some effect?