Definitely Mold. Ear wax in the wrong part of the ear canal can do that, too.
I lost my immunity to Mold about 10 years ago. I coughed for months. It started from a leak in the roof which after we left the house I had fixed by someone else. I also bought an Electronic Air Purifier. Afterward I found out that they produce Ozone which also triggers coughing fits in me LOL. I went to an Allergist/Asthma Doctor and got started on shots. BTW allergic reactions like coughing can closely mimic Asthma especially if Ozone is involved. On the Air Quality Alert days I have to stay inside as much as possible.