At home, my Droid Razr Maxx is fine.
Away, I better have it off of Wifi, (even if there is free Wifi), otherwise my phone gets hot and very very slow. Even on the highway!
Last night, I was in a restaurant that had free WiFi but really bad service, no 3G, no 4G, so I tried the WiFi but my phone did not want to work at all.
When I visit my parents, (1 1/2 hours away), my phone is so sluggish and gets very hot I get very frustrated with it.
Of course when I was in a Verizon store the other day (problem with my daughter's I-Phone), my phone was acting fine.
So whats up with this?
It may be getting hot because it's looking for a signal. Sometimes putting the phone in airplane mode for a minute or so will help it locate a connection. You also might try turning off the phone, removing the SIM card, waiting a minute or so, then replacing the SIM card and turning the phone back on to establish a fresh connection to the network.
If you're in a bad signal area it's best to shut off mobile data. The phone will just constantly be looking for a signal and trying to connect. Not only does that make your phone hot but it drains the battery.