My Iphone 6 is overheating.
Whenever I use apps such as fb for a long time (let's say 10 min) my phone starts overheating and losing battery very fast, also when I use it as a hotspot.
iPhone 5, iOS 6.1.3
There is no iPhone 6 so there is no way this mythical device can be overheating.
If you actually have an iPhone, basic troubleshooting from the User's Guide is reset, restart, restore (first from backup then as new).