Sound not working. Null sign is where the volume level should be.

I can hear the start up sound when I turn on my Macbook Pro. When I try to raise, lower, or mute the audio- nothing happens. The audio is crossed out at the top, and at the bottom, there is a null sign (prohibitory symbol or a circle with a line across) where the volume level should be.

The audio works well with bluetooth buds but not with headphone (same problem: ∅).

I already tried restarting the macbook, force quitting the 'coreaudiod' process in the Activity Monitor, and conducting a PRAM reset. I would really prefer not having to take it in to the store. Any other suggestions?