When I started flying T-37's in USAF pilot training I noticed an issue with trying to clear my ears on a rapid descent (think spin recovery). All the air was going out my left ear and my right ear stayed blocked. I had to work my hand inside my custom fit helmet and block my left ear canal then valsalva. At that point I was out of hands and had to fly with my knees. I went to the Flight Surgeon and he said not to worry, probably just a slight cold. Much later I realized how lucky I'd been, it could have gotten me kicked out of training.
So I put up with it for the rest of T-37 training. The T-38's were pressurized to about 14K cabin so I didn't have much of an issue. Then I flew C-130's and again not to much of an issue. Then one day I get orders to be a T-37 Instructor in Del Rio, TX. Hmm...No
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I went to the Flight Surgeon who couldn't find the cause. Then I was sent to an ENT Doc and he said grafting some skin onto the ear drum should fix it. So I had surgery, 30 days off from flying. They gave me a test where they blow air into both ears and measure resistance. It showed normal so I was good to go. My orders had been delayed and now at least I had a better base but still did not want to instruct in T-37's. Started flying C-130's again and the issue came back. Next thing you know I'm seeing the regional ENT Doc at Andrews AFB. He puts a neutral solution in my ear and has me valsalva. He sees the trail of bubbles but can't confirm the reason. A few weeks later I'm off to see the Chief ENT Doc of the USAF at Lackland AFB. This Doc was a bird colonel and knew his stuff. He figured out I had a "trap door" in my left eardrum. That's why the results varied. He said it wasn't enough of a problem to have surgery again. So I basically dictated a waiver letter to him saying I was limited to flying Tanker, Transport, Bomber aircraft. So I stayed in C-130's and then flew airlines and corporate for many years. But what a CF to go thru.
For the OP this all happened to me in the mid 1980's. I'm sure the tech has gotten many times better and getting that fixed **should** be a simple matter.