Sound not working on my LG TV. How to fix?

The sound stopped working on my lg HD tv. I have a chromecast and a digital reciever connected to it via hdmi. Sound doesnt work on any devices connected via hdmi. I swapped cables, reset devices, etc. Nothing works. I tried a regular satellite reciever connected via rca a/v cables. Same thing. No sound. I ran a sound test on the tv and it was successful. I connected an external HD via USB to it, and movies played with sound perfectly. This leads me to believe that the USB port is working fine but that the other inputs are not. Any suggestions on how to resolve this extremely frustrating issue?