Hi, It is most probably due to infection in the sinuses leading to Sinusitis and as the sinuses drain through nostrils, therefore fluid/pus accumulation in sinuses can drain through the nose. I would suggest you consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like PNS view X-ray 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 Pseudoephedrine, an antihistamine like Levocetirizine to control sneezing, 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 I have answered your query. Let me know if I can assist you further.