Is It Normal For A Cough To Persist For Over 6 Months Despite Using Montek LC?

Hi , iam 26 iam suffering from cough from more than 6 months, not the dry cough I went to many hospitals but there is no result, when I went to doctor he confirmed my esr was 35 nd he suggested montek lc if i stop using the tablets then iam getting cough again and feels small sound from my throat when ever I get cough and done the chest scanning also everything was fine ,,,, now iam using montek tablet when ever I get more cough,,,,please suggest me what to do