Hello, I am a 34 years old male use to feel shortness of breathing intermittently that last for few hours or sometimes 1 or 2 days for last 10 years which subsides automatically. But for last 3 months I m feeling same problem frequently that subsides while taking duty off for 1 or 2 days ...i did ECG echocardiograpgh chest X-ray R/E blood Tyroid profile creatinine.. All are normal. Except PNS x ray that shows right maxillary sinus haziness..What would the probable cause of this breathing proble