Thanks for your question on Health Care Magic.
I can understand your concern.
Breathlessness in a person who smokes is due to COPD or
chest infection. Get a chest x ray done, if your chest x ray is normal, no need to worry for
lung infection.
Possibility of COPD is more in your case.
So better to
consult pulmonologist and get done clinical examination of respiratory system and PFT (Pulmonary Function Test).
PFT is needed for the diagnosis of COPD.
It will also tell you about severity of the disease and treatment of
bronchitis is based on severity only.
You may need inhaled bronchodilators and inhaled corticosteroid (ICS).
Also STOP
SMOKING at the earliest.
Don't worry, you will be alright.
Hope I have solved your query.
Wish you good health. Thanks.