What Should I Do If My Infant Post Nasal Drip With Throat Clearing And Swallowing Hasn’t Improved Despite Treatment For Allergies And Acid Reflux?

I have a post nasal drip it s been 4 months now and it won t go away....i used to smoke hooker when it all started and i stopped smoking. At first i had a persistent cough but it went after 3months now I m constantly throat clearing and swallowing. I did see different doctors one is saying it s post nasal drip or allergies and the other one said it s acidic reflux i tried their prescribed medication but it s not working what can i do?