It could be a number of things so seeing an ENT if it continues is a good idea... I know for me part of the problems were some food allergies that I was constantly getting ear/ throat and sinus infections that antibiotics would not clear up. I am not saying it iss this by any means but just saying could be a number of causes for that sort of stuff. Also for clearing the sinuses I recently purchased a sinus rinse as someone suggested on here to me, not the nicest to use but works great. Hope you feel better soon.