My monitor on my PC has it's speakers built-in, so I'm guessing maybe yours is also.
I know that when I had a PC with external speakers I had no sound (volume) problems (except I got yelled at for having the volume too high - lol), the volume could reach really high levels.
My mum's PC has external speakers, the audio level is much higher than the audio from my monitor with the volume at it's highest.
Amazon have some good priced speakers. [*]