No sound from audio jack, built in speakers work

[scratchd0g]

I am running Ubuntu 18.04.2 on an iMac (dualboot with MacOS) and i cannot get sound to work with headphones. I have tried a lot over the past two days and I have made no progress, even with the troubleshooting guide stickied here. Sound will work with the built in speakers and through bluetooth. I am new to Ubuntu so if I am doing anything wrong please let me know.

[rmpeake]

Hi, scratchd0g,
Welcome to Ubuntu forums. Do you get any sound at all? From the system? If you plug in an HDMI cable do you get sound?