The audio output that is connected to the motherboard are giving me issues

[ArgenisXD]

PC Specs

Motherboard: Asus z170-k
RAM: Corsair Vengeance 16gb
CPU: Intel I5 6600k
GPU: EVGA 970 axc 2.0
PSU: Evga 750b

I been using this PC to game for a few months now and all I ever used was a USB headset (plantronics gamecom 780). My headset broke so I had to use some headphones. I plugged the headphones into the front panel for headphones and I noticed that it only plays on the right side. I thought it wasn't a big deal so I connected the headphones to the back onto the motherboard and it did the same exact thing except when the sound came from the left instead of the right. I went into the sound settings and checked all the settings and the balance and everything was fine. I updated my realtek drivers and any other driver I could find and still have not found anything.

I borrowed some USB headphones and the sound works perfectly on both sides. It also worked perfectly on my broken headset. I googled for as much info and could not find anything. I tried the windows troubleshooter as well, I rolled back drivers and checked device manager. Everything seems fine.

 

[Lutfij]

Given your current gen specs, I'm going to assume you're running off Microsoft's latest platform, Windows 10, if not please correct me. That being said, first disable automatic device driver updates, uninstall and reinstall your drivers using either:
a| An elevated command i.e right click installer>Run as administrator
or
b| Run in compatibility mode:
Right click installer>Properties>Compatibility tab>Windows 7/8[from drop down menu]

You might also want to see if you've gotten your BIOS upto date alongside any and/or all device driver updates from here.

The end result may not be favorable because the case found all over the www is that folks on Realtek audio solutions running on Windows 10 have either given up and bought a dedicated sound card or have just dealt with it using a USB powered headphone. Mind you, USB powered headphones rely on the USB port or inline sound card to do all the sound processing which explains why the issue wasn't apparent when you were on the Plantronics.