Hi - I think that what you might have is COPD. I, too, was a heavy smoker but, even though I stopped smoking 30 years ago, I was left with problems related to my habit. Before I stopped smoking, I had a terrible cough, bringing up lots of sputum. I just wrote it off as a "smoker's cough" (which they did in those days). However, I was told that I should stop smoking cigarettes. It's a terrible habit and very, very hard to get rid of. But, it is possible!!!! And, you must stop smoking! It took me a while (sneaking cigarettes, stopping and starting, etc.), but when I finally was able to stop for a week, my cough had completely disappeared! However, I was still left with damage to my bronchial tubes and have been diagnosed with mild COPD
COPD can't be cured, but stopping things that are causing it can help greatly.
I hope that you will stop smoking immediately. After one week the nicotine will be out of your system, and even though occasionally you have the desire to smoke that will gradually deminish.
Believe me, you will be so happy that you stopped smoking!!!!