I have this as well as other symptoms: periodic sneezing, swollen tonsils, drainage, and susceptibility to sinus infection. I've been to ear/nose/throat specialists since I was 6 years old without a helpful diagnosis. It's part of the reason I don't trust doctors to this day. When I was younger and living out West, they diagnosed me with asthma and gave me an inhaler despite me never having an asthma attack. I've had roughly 50 needles poked in my back checking for allergies, all negative. One thing that has helped is increasing the humidity. I spent a week of one summer doing a Boy Scout summer camp in Eastern Tennessee in the blistering heat and humidity...never felt better in my life. I have a humidifier for my bedroom which also helps.