Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern.. As per your complain severe pain and pressure in ear after sniffing the nose leading to muffled hearing along with loss of hearing can be due to injury to Ear drum due to excessive pressure difference across the eardrum due to vigorously sniffing leading to perforation.. I would suggest you to consult an Otolaryngologist and get evaluated.. He can also do an Otoscopic examination of the inside of the ears.. In case if there is any perforation he can advise you a course of antibiotics, anti inflammatory painkiller, decongestant Oral as well as Nasal Spray along with antibiotic ear drops.. As you also have sinus infection a PNS view x Ray can help in ruling out the exact status and can be treated with antibiotics , anti inflammatory painkiller, decongestant nasal spray, saline nasal irrigation, Steroid nasal drops, steam inhalation and use of humidifier in your room.. Warm compresses around nose can help.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.