What Causes Sudden Onset Of Dry Cough Post Hernia Surgery?

Hi! My mother has been operated for hernia two weaks ago.she is on medication now -combiflam, Relcef-500, Telma-AM, insulin injection and Pantop-dsr.But for the past one week she is suffering from dry cough and no medicine is helping her. Also her tests are normal.I want to know is the cough due to any side effect of any of the above medicine?