Why does my LG G3 restart randomly??

[AC Question]

My G3 is just restarting randomly and it pisses me off...
What happens is it starts getting really hot on its upper part (just above the battery) and becomes really slow and it's hard to do anything on it, it just feels like a really old computer with poor internet connection, then it restarts and repeats the same thing, what can I do here? Thank you in advance!!!

 

[belodion]

Is the battery good?

 

[visinedrip]

Mine was doing that too after updating to Marshmallow 6.0. Replaced the battery and no dice. Got very hot and restarted randomly. Scoured the internet and then found a tip that seems to have worked for me.
Disable 'Activity Logs' in Settings > General > About Phone > Activity Logs (Uncheck)

For some reason that fixed my issue. Maybe it'll work for you too!