Suggest Treatment For Cough And Shortness Of Breath

Hi, 37 yrs old, former smoker for 10+ years, maybe 1/2 pack per day. Recently quit and have an extremely subtle cough (it barely exists but the sensation of needing to cough exists) and have been having shortness of breath, especially with exercise. I had a PFT and most of the # s were above 100%. The FVC,FEV1 were over 100 and the ratio of the 2 was over 80. My pulmonologist still diagnosed me with mild asthma. I have been looking online and trying to understand his diagnosis but I m having a hard time. Their was no significant response to the bronchodialator noted in the test but there was a 21% increase in the FEF 25% (not the FEF 25-75 - that was over 100 and didn t change much after the inhaler). Is a change in the FEF25 a measure to be used to diagnose me with mild asthma ? Are there other numbers that I should be looking at? Everything I have read indicates that my PFT would be classified as normal but I assume there is more to it. He gave me affair 100/50 and a rescue inhaler.