I developed pneumonia, wheezing, doctors don’t know what is wrong?

In October of 2015, I developed pneumonia. After that, I developed a intermittent wheeze. Since then, I have had pneumonia two more times. I have a history of smoking, I am a 32 year old male, and I have no pain or discomfort. I only have wheezing (more of a rattling) that only occurs a few times a week, no shortness of breath, no pain or tightness in the chest, and white to yellow mucous that is produced when I do cough, which usually occurs only when I wheeze. Albuterol inhalers seem to work, but the doctors don’t seem tow know what is wrong. I have had pneumonia 3 times. I take Lunesta, Prazosin, Celexa, and Welbutrin.