Hello
As you mentioned that when you smoke there develop cough i.e. smokers cough . 
This is not because of any disease rather due to SMOKES inhaled by you in lungs . The smoke produces 
allergy in airways and this allergy causes 
bronchoconstriction and this causes 
bronchospasm . 
This bronchospasm produces whistling  sound or wheeze in airways ( lungs ) and cough . 
So reason of cough in your case is smoking .
If you will smoke continuously there will develops ASTHMATIC ALLERGIC 
BRONCHITIS and this turns into ASTHMA .
I am writing about "
nicotine replacement therapy ".
Drug        Available strength      Dosage                                        remarks
Nicotine       2mg/gum               6-12 /day x 3months           stop smoking 
gum            4 mg / gum           before gradual reduction       completely.
Nicotine inhaler , Nicotine lozenge , Nicotine 
nasal spray , 
Nicotine patch available  everywhere so you can use . 
In my opinion at once consult a physician and get rid of smoking .
Good luck.