How do you fix your sound on the MacBook Pro?

Answer 1

You did turn the "mute" off right? Via the Sound keys.

System Preferences/ Sound and see if the internal speaker is selected if you don't have external speakers connected.

If you have external speakers or plug in a head set you have to chose them in the same place, it may show up under "Line Out" more then likely.

SoundSource is an application that puts a drop down menu in the upper Apple menu bar to make it quicker to switch back and forth, there are others out there also.

Answer 2

Sleep your mac then open unsleep it then try the sound.