phone heats up

[Haneefzamuran]

Mu phome heats up while charging.whats may be the reason.some times It also heats up while being used.

[Tkokab]

please mention which model you are using.
Restart your phone and update to newest software available.
try to change charger and cable and use the one which came with the phone.
At last reset your phone to factory default.