Suggest Treatment For An Ear Infection

Two years ago when I first became pregnant I had a really bad sinus infection and two ear infections. Because I was pregnant , My Ob/Gyn looked at my ears for me and said he could see a terrible infection in my left ear. My right ear actually hurt more than my left so I know I had an infection in there somewhere ( maybe further back?) My ears both felt full and it sounded as if I was underwater. I was treated with three days of Zythromax. It took several months for my ears to clear, however my right ear has never felt normal since. It still feels like there is a bubble in it. I went to an ENT specialist who told me that my eardrum looked fine and that my hearing test/pressure was fine as well. It seems that sometimes it feels worse (as other peoples do) when I have congestion, etc. The problem is that mine NEVER clears! I am constantly trying to "pop" it with my jaw as you would on an airplane. It drives me crazy because it is a normal reflex to try, but it never helps! I don't want to spend the rest of my life like this! I think there must be some kind of damage to my Eustachian tube, but I don't understand why the doctor couldn't detect it. It doesn't hurt, it is just really annoying!! Please advise me on what I could try next. I would greatly appreciate your help!! Paula B.