Alright guys, I have limited experience with anything involving car audio or cars for that matter.

Here's the problem. Their is a high pitch constant noise coming from the trunk of my 94 Z28 camaro. (Stock Bose system.) The sound is best described as a sound you would here in a blown power supply unit on a computer or an old CRT monitor that starts to go bad. I believe the sound to be coming from my speaker back there.

What are the chances it's my speaker? If so, how do I go about fixing this problem? Just install a new speaker? Is it easy to install a new speaker?

bad amp most likely

easy to install new speaker
is it a constant noise? or do you hear it when you apply the gas?

i get it too and i have no idea what it is, its a constant squealing noise. Im glad my exhaust drowns it out lol.

It's constant. Starts up immediately after I turn the car on and doesn't change with acceleration.

you've replaced your stock stuff tho right? if so its not his speaker/amp making the noise.

My car has the stock system.

Sounds like the factory amplifier. Don't get an OEM replacement. Either bypass or replace with aftermarket.

seen this problem before, try to redo your grounds from the motor to the frame and the ground from your battery to the block.
it fixed the problem we came across here...

Thats usually the case when the pitch of the sound changes as you rev the engine.