Man, you were taxing the heck out of the thing: charging wirelessly and routing out data through the lightning port and running Maps? All on a pretty memory intensive beta (judging by the many resprings I get). You're lucky your phone didn't slag and melt its way through the charging pad! 😀
I've had a lot of heat ups too. Usually using weird things (like Words with Friends [don't judge me ... at least those of you who haven't already!])