I have got less hearing specially in left ear from sometimes. It happened 2 years back as well, at that time doctor inserted a long pin through inner ear skin and pull out fluid using a machine. It increases specially when I get running nose/cough in winters. I have got same kind of problem 2-3 times in my life. however, a doctor advised I should blow air through ear by closing nose and it sometimes open but not sure if that's how it should be treated. Kindly advise.