I got a normal cold on Halloween Day. It went though the normal channels and the cough was pretty bad for about 3 weeks. The week before Thanksgiving I still had a cough but not that bad. Two days before Thanksgiving we got a new Heating and Air Conditioning System. I have not gotten over this cough. I do not cough all day long but a few times during the day and sometimes at night. Could this be related to my new air system, weather, etc? I feel perfectly normal otherwise, no fever, great appetite, no weight loss and not out of breath. Should I be concerned? I smoke about 5 cigarettees a day?