If you’re hearing something you need to know the range you can hear and this gives an idea of frequency. As someone said above unplug and reboot everything. https://youtu.be/-E1SDl9vLo8

Edit: there’s a 30000 hz tone teens can hear. Now I’m going to throw in there’s a sleep thing where you might here noises that aren’t there right when dozing off and waking up. I mention because it’s common. It’s annoying. A lot of people have it. Here’s the name. It’s not a mental disorder. Stick Earplugs in and see if you still hear it. hypnogogic hallucinations

Also grab a different set of headphones.