Hi.. Thanks for the query. I have gone through your query and can understand your concerns.. As per your complain it seems that post nasal drip is due to Sinus infection only and it looks like your Infection is lingering and has not yet completely subsided.. I would suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like PNS view x ray or MRI scan can help in diagnosis and treatment can be done accordingly.. You can be advised a course of antibiotics, anti-inflammatory painkiller like Ibuprofen, decongestants like Pseudoephadrine, do saline nasal irrigation, steam inhalation and use a humidifier in your room.. You can also be advised decongestant nasal sprays containing Xylometazoline or Oxymetazoline.. Avoid spicy and chilled foods.. Do warm compresses around nostrils.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.