Read this: this might also work on AT&T Optimus G Pro E980. Also, there shouldn't be any damage to your phone if you follow these instructions exactly. Of course, I messed up my phone the first time I tried to do this... Proceed at your own risk
I discovered that the tethering functionality on my Optimus G was a pain to enable. After trying pretty much every free app on the Play Store that claimed to do hotspot, I discovered that AT&T must have a LOT of pull with LG. Unlike the popular samsung galaxy devices, you couldn't just download a hotspot toggle and be done with it. Also, FoxFi didn't work either (or at least the trial didn't).
Then I found a tethering app that required root. It worked after rooting my phone, but I couldn't get the WiFi back up afterwards without a restart. So in the end, I decided to get the built in tethering functionality to work. More after the jump.