when I press my macbook's touchpad, the computer makes a weird noise as if something can't move properly inside

The haptic feedback motor is a tiny electric motor with a weight attached, similar in principle to the "Vibrate" noise-maker in an older cell phone.

Is it about that loud, and could that be it?

I think it is supposed be simulating the look and feel of a "click" on the trackpad.

If you have access to an Apple-owned store, your appointment for an evaluation and diagnostic is free, in warranty or out.

I have found that if they can fix something in a quarter hour or less, without using parts, they will often try to do so. Apple wants you to be a Happy customer.