bravesoul247:
Unfortunately, there’s no single answer to this question. Sometimes phones get hot as the result of too many apps running in the background. A bad battery or other hardware problems cannot be ruled out. Other times, it’s because of a malware infection.


Here’s the thing: All phones can, and usually will, get a little hot from time to time. But it becomes a problem when your phone heats up to the point where you cannot even hold it,
Below are some reasons why your phone gets hot.


1. You’re gaming… a lot!
As you use your phone to play game,the device uses its Processor, GPU,Ram,Rom, thereby making the phone hot .

2. Too many background apps
The more apps you have running in the background, the harder your phone has to work to maintain them. Generally speaking, background apps are not typically a problem. However, if you never go into settings and turn them off, they could turn into one.


3. Using the phone in direct sunlight
Your phone will get hot due to the extra heat it's receiving from the sunlight,it's advisable you don't use your phone for long under direct sunlight.


4. App and Os Issues
Certain bugs in apps can cause your phone to overheat or misbehave. Same goes for your phone’s OS. Because these apps have to run on different types of devices using different configurations and operating systems, they may act optimally on some, less so on others. The best way to stop them from malfunctioning is to keep them updated.


5. Virus
Yes virus can make your phone to get hot too, Since malicious apps are usually unoptimized pieces of code, they attack your phone’s CPU and memory, throttling them and generating a lot of heat,that's making the CPU to overwork thereby generating more heat.


Cooling Your Phone Down.

1. Turn off that app that's running in background and consuming resources
2. Remove the phone case
3. Turn off unnecessary settings,like BLUETOOTH,GPS,WIFI.
4. Use phone master to clear junks
5. Update your apps and phone.


Anything that keeps your screen on for long periods of time and uses your phone’s GPU will cause the device to heat up.

Source:https://spot.tecno.com/ng/forum.php?mod=viewthread&tid=78385&ordertype=1&pid=271275#latest

personally I think heavy usage causes hotteness