Dear Mahendra ji
Welcome to Healthcare forum
is just the sign of many health disorders like tuberculosis
of lungs, lungs cancer etc. That time perhaps it was tubercular infection
so you had taken the 6 months of treatment. Now why it is coming in your mind that you may again get any disorder. the most important thing is if you are leading a healthy lifestyle and healthy diet habits and early detection and treatment of any abnormal sign and and symptoms there are less chance of getting any major health disorder. quit smooking if u have. Your lungs capacity can be improved if daily practicing breathing exercise
. Daily do pranayam (breating exercise) for 10 to 15 minutes and if getting any cough
or breathlessness contact to your doctor for treatment.
Wish you best of health. Take care