Hi Shuravi85,
Let's make sure your iPhone is up-to-date with the latest version of iOS:
Update your iPhone or iPad
If you're not seeing a message that your iPhone needs to cool down, then it is not overheating:
If your iPhone or iPad gets too hot or too cold
It can be normal for your iPhone to be warm under use, especially when charging.,
If you've only just gotten your iPhone, it's going to expending extra energy indexing, downloading, and syncing your information from a first time set up.
To check to make sure no unexpected app is using a lot of battery, check for battery usage here:
About the battery usage on your iPhone, iPad, and iPod touch
Thanks for using the Apple Support Communities.