A 42 years old lady complaining of cough on and off for one and half months, not responding to the treatment given And all investigations are normal except X-ray chest. BP, pulse, ESR, CBC RFT NORMAL. LFT = S. BILIRUBIN 1.2MG, SGOT, SGPT 52,50.

My query, what is the cause of a cough, in this case, is cardiac or pulmonary or GIT? What X-ray chest is indicating?