What Causes Shortness Of Breath?

I am 28 years old with a history of irregular smoking cigarettes, maybe 1 per day on and off with nothing regular, and a history of marijuana smoking, regular for 10 years but discontinued now. I have not had shortness of breath until recently. I kissed a girl who went to an urgent care clinic earlier that day complaining of shortness of breath. She was told it was asthma and it was not contagious. We kissed, and a couple of days later, I have developed shortness of breath. My doctor prescribed me a z-pack, an inhaler, and asked for a chest x-ray. The chest x-ray revealed what the radiologist called mild pulmonary hyperinflation otherwise negative chest x-ray When I look this up, it says COPD and emphysema, and my doctor referred me to a pulmonologist. I had a chest x-ray about a month and a half before this to check for TB for a health screening to enter China, which I will do next month. No TB and no comments about hyperinflation. My symptoms started after I kissed this girl. I m still experiencing shortness of breath or the feeling that I m not getting enough air in.