First check your phone case, is it blocking your phone from ventilating? You may need to clean the lint and debris from the case so your phone can breathe. If you are using a case that was not made for your phone, that could be your issue.
It may also be your software. Too many applications open at the same time will overheat the phone and drain the battery. Close the applications that cause the most battery drain like your GPS. Turning down your screen brightness can help as well. If you are unsure how to check your software and battery for issues, check out the LG G2 Sprint troubleshooting page(link below) for some great tips!
[[LG G2 Sprint Troubleshooting|new_window=true]]