After a really loud noise like a live concert, you may start to hear a high-pitched noise. You can also hear it sometimes if you're in a really quiet place. We call this noise "ringing" and use it like this:
My ears are ringing.
There's a ringing in my right ear.
"Ring" is the same verb which describes the sound of a bell:
Whenever the fire alarm started to ring, we'd all shuffle outside and stand in front of the school building.