Hi doctor, Since few months I am feeling short breathtaking mostly during night's. I felt it 4 to 5 times since 4 months this stays for 15 to 20 mins. I use to smoke heavily earlier in order to stop smoking I started smoking electronic cigarette for 2 years. Now I have quit even that. I feel like this mostly in closed areas or small space. It feels like my lungs don't supply oxygen or pump some time, I have to take long breath but I still feel oxygen is not enough, this is really annoying me. Please let me know what it would be? If it's bad please let me who should I contact preferably chennai Thanks