Right ear for over the past 25 years. I hear it now only because you made me think about it. Seriously though, after a while you really don't notice it. It's just there. Mine is caused by fluid that builds up in the Eustachian tube. No idea why, but it developed in my late 20's. I have had a couple tubes put in and the fluid drained, which only seems to last about 18 months, then the tube fall out and the process repeats itself, back to half deaf and ringing on the right side. Stupid, tiny little tube costs hundreds of dollars to have put in (and can be done in less than a minute), so I just live with it. My Dad had it, but his was hereditary, His whole family, all the men had it and many passed it down. I'm adopted, so mine is from a different source. Probable allergy/infection, but no idea which one causes fluid to build up behind my eardrum and Eustachian tube.