I went for chest x-ray, lung check (asthma), scope (I think its endoscope, the kind of scope the doc
uses to put into the nose). I have also tried all sorts of medication after the checks; nasal spray, flu medicine, gastric pills etc to eliminate the potential causes. I have also tried traditional chinese medication.
Its been 2 years and I'm still coughing away. Sometimes it gets so bad that there would be a stitch in my mid waist and I feel like throwing up.