My computer makes a very irritating sound. I think that it is coming from either the monitor or the speakers. It is a very high pitched sound, but it is fairly quiet. Do you know what it is and how I can make it stop?
It’s the monitor, not sure how to stop it.
First step - switch off the monitor. Can you still hear it? then it’s the speakers … if not, it’s the monitor. 
Except, that monitors can put out audio frequency noise that the speaker wires can pick up. Shutting off the monitor might also quiet the speakers. So move the speakers away while the monitor is on, see if the noise reduces, and if not, then try turning the monitor off. (For this and a lot of other reasons, you don’t want your speakers close to monitors anyway, even if they are shielded.)
If the monitor is making noise, there are extremely few options for consumers to try and fix it. Basically I would only recommend trying different resolutions and refresh rates. If that doesn’t work, most other likely fixes require a professional technician. A DIYer can die from being a DIYer when it comes to monitors.