What do i have? i keep on coughing and my lungs itch; alergies? Bronchitis? emphysema? ??

This happened to me a while back and I also quit smoking, I am 26 and smoked since 16. I was very worried but finally it has gone away. A doctor never gave me a good diagnosis, only ruled out stuff. After tons of searching online I guessed I had sinusitis (but was still worried about COPD.) At our age the odds of emphasema are really really low so try not to stress. Try to manage on OTC's and it will go away eventually, trust.