What's wrong with my lungs?

Hi, I've been going through a phase I guess for the past year. First I was diagnosed with bronchitis and then they diagnosed me with a very mild case of asthma. But I've asked my family members who had asthma and they didn't cough up Flem. Whenever I feel short of breathe I can induce a cough and I can cough Flem out of my lungs. What is this? Is this asthma? is this bronchitis? is it an infection? Help is appreciated thanks!