Talk to Pediatrician on 3 Yearsold Daughter Coughing

my daughter is 3 years old she is coughing with congestion gor about 1 month kanhi thek hojati hai phr hojati hai dr said isko allergy hai dr recommed to her zatofen syrup and mytika sachet he said give her for a month do this course phle ye kiya ta fark parh gya ta but ab itni khansi nai hoti but congestion thek nai hota hai uskaa... or mera ik beta bhi hai 1 month ka uska chest bhi congestion hota hai but flu wagera nai hai usko ... do tell me what to do...??