phone is very hot

Depending on carrier usually in Sprint zone or my Verizon there is a support section which you can run a diagnostics on the battery life/usage. That will show what is using the most battery charge.

Now for the phone getting warm. LG’s (I’ve had the G5, X, and now the G7) all of them have had a horrible issue with heat dissipation.

some things to take into account, do you have mobile data enabled? If the phone is constantly switching between 4G/3G/1X then this would account for the heat & battery drain. or are you possibly in a weak cellular signal area? If it's constantly trying to find a signal then the same thing could happen.

A way to test (which can be a nuisance since we usually need our phone) is charge it up and place it into airplane mode. If it continues to overheat and drain battery there. If the issue goes away then it is definitely one of the issues with data/signal. If not I would look at replacing battery. As for the heat… there may be a couple applications that assist in identify battery life issues but I hope we don’t have to get to that point.