Why does my ear keep popping?

It happened again today - while tuning my cello and using all my strength to turn the stubborn C-string peg, boom my left ear popped.

This has been happening more frequently lately. It usually occurs when I’m engaged in some physical activity that makes me grunt and get short of breath, but I can just be walking along talking with friends and it’ll happen. It does wonders in pissing me off, because I’ll be deaf in one ear for sometimes hours at a time.

Any explanations? I’ve never had ear problems, but have had sinus and throat problems for years - could that be the cause? But why during exercise?

It’s related to your throat and sinus problems.

The Eustachian tube leads from the backside of your ear drum to your throat. Its function is to keep the air pressure equalized on both sides of your ear drum. When it gets clogged you can develop a pressure differential that impairs movement of the ear drum, resulting in the partial deafness you describe.

Popping is when a ‘burp’ of air gets through the clogged tube.

Have you been tested for allergies? Allergy therapy and a combo decongestant/antihistamine has helped me.

But also, gargling with warm salt water may help some, since that can help to unblock the Eustachian tubes.

Good luck!

You can try taking Sudafed for a couple of days and see if it improves. My Mom has chronic ear problems and her Dr puts her on Sudafed all winter, to keep the tubes open and prevent infections. It seems to work pretty well, and it is an over the counter drug, which you can get in generic forms.
Remember IANAD and YMMV!!