First of all I welcome you to HCM, I have noticed that you have mentioned post nasal drip due from my sinus infection . I guess you had already undergone an X Ray OR CT Scan. Straightly going to answer your query, i would say that Abroxol will definitely help you relieve your symptoms (as Ambroxol is a mucolytic ) , BUT if the sinus (any of the sinus) is full of secretion and thick enough to drain freely, you should better undergo go surgery (i.e., FESS). So clearly it depends on condition of your sinus at present. At any case Ambroxol will definitely help you whether you undergo surgery or not but may not cure you completely. Going through your history I assume that you should go with your doctors advice and go for surgery as you said you had horrible post nasal drip . I hope i could clear your doubt. I wish you an early recovery and a very very Healthy life. Take care of yourself and stay away from dust as much as possible. Thanks