Overheating is a common phone problem because it can lead to other problems such as battery life and performance. An overheated phone can also cause the device to shut down in order to protect itself from damage.

Solutions

The first thing you need to do is check how much space you have available on your device. To do this, go to Settings > Storage > Internal Storage. This will show how much storage you have on your device and also how much storage is used by apps and other files such as photos and music.

If there's not enough space left on your device but only a few apps installed recently then deleting them may solve the problem (but only if they're not essential). You can also try uninstalling unused apps from the Play Store or from Settings > Apps & notifications > App info > Storage usage > Clear cache or Clear data (this will remove all cached data for an app).