Just make sure your using the OE Charger or high quality charger that is designed for your phone/device.
Just because a charger it fits or has an "IC Chip" in it can mean squat due to low quality chips. The low quality chargers can damage your device and / or battery.
The proper charger will also stop charging when it is charged if its working correctly which is usually true with the OE Chargers.
Yes, they do heat up while charging especially if the battery is low, may get warm but should not get hot, you can check the battery temp with free APP or thermometer.
Its also good practice to top off the battery vs deep discharge cycles.
Hope that helps