my sound built in output is not listed i cant get sound out of my mac

Go step by step and test.

1. Reset PRAM:  Reset NVRAM or PRAM on your Mac - Apple Support

     Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, 

     and recent kernel panic information. 

     The settings stored in NVRAM  depend on your Mac and the devices that you're using with your Mac.

2. Reset  SMC:   How to reset the SMC of your Mac - Apple Support   Choose the appropriate method.

    Quote:

    Resetting the system management controller (SMC) can resolve certain issues related to power, battery, fans,

    and other features.

3. Launchpad > Other > AudioMIDI Setup > Sidebar > MacBook Pro Speakers > Output

    Make sure  no item under Mute is enabled.

4. If you see red light in the audio output port, plug in the headphone jack few times to flip the switch.

5. Try suggestions given in this article.

      https://support.apple.com/en-us/HT203186