Thank you for your query at DoctorSpring.com
There are two possibilties for chronic mucus, leading to coughing. One is LRTI, and the other one is recurrent allergies.
I will like to know what medicines have you tried already?
Also it is better to try a good respiratory system specific antibiotic like Pulmocef 500 mg twice daily for 7 days along with Tab. Montelukast-Levocetrizine once at bed time daily.
This will surely help your symptoms.
Feel free to discuss further,