My Son Is 3 Yr Old. He Got Cold Cough

My son is 3 yr old. He got cold cough in every 8 to 10days gap .I have never gave him somva 34 and gripe water from his birth to till now apart from this most of the time have to give him Antibiotic to cure his disese .his diet is full of veggie fruits also. M fed to see him. He some time eat chocolates,candy, biscuits but very less. And he was on top feed. From last 19days he cough in middle of night .plz help