Hi,my son is 5 year old,from 2-3 years he has cough problem,we have consulted many doctors all they tell is that it's normal cough but he has cough every month despite many restrictions on food triggering cough. On one doctors recommendation we avoidef giving milk at night,and it was effective also but then also it made not much difference after sometime. Please help and recommend what test can be done for right diagnosis and right treatment.