I am 35 year old male. I am suffering from extreme cough which continues from several seconds to 1-2 minutes. Sometimes I pass out during coughing. I have slightly warmer body upto 99. 6. I pass white bubbly phlegm, some time little pale. Sometimes during coughing, I have to vomit. This is from more than 2 weeks. I have shown it to doctors who have my chest x-ray and it is clear. I have shown it in plumnory medicine clinic. The pft is also ok. I get tried soon. What it can be?