Coughing leads vomiting. For treatment.

Having no other illness except this one. Its been nearly 10 years, suffering from severe coughing at night, especially after dinner and as soon as hitting bed. Coughing is so much whopping that entire apartment perhaps hears. Most of the time, this leads to vomiting badly and as soon as vomiting done, coughing goes away!!! Since last few months, this coughing is just unbearable, coughing makes entire body shaking, sometimes vision becomes blurred for few seconds. Consulted so many world class highly qualified Doctors (Medicine, Pulmonologist) at Hyderabad's No 1 hospital, but no progress, all failed. Guess, they even could not diagnose what actually causing these chronic monster coughing. Their Trial & error treatment just suppresses the coughing for few weeks, but re-occurs. I have no diabetics, gastric, asthmatic or cold allergy, no smoke; had Pneumonia in 2006. I cannot bear facing hot weather, so, always in AC. Pls advice which specialist doctor and where I can go for treatment.