I Saw A Dr Who Told Me Because Of My

I saw a dr who told me because of my ct with contrast that I had copd. he said the ct showed hyper inflated lungs and a small nodule on my left lung. I asked him why I had this and he said because I don't smoke he doesn't know. I saw a cardiologist who said my heart was fine. when I went back to my pulmonologist he then retracted everything he had previously said. I have problems with breathing and getting enough air sometimes. I have had problems for years when I run It always has felt like my lungs cant keep up.
I am at a loss as to what is exactly going on and can not get an answer.
any ideas?