My iPhone 6 heats up while using near power button right where a8 chip

My iphone 6 is working perfectly all the functions are working as they would be working,no water drop nothing but im little bit worried just because whole screen is not warm just that part of screen gets a little bit hot where a8 chip is located only when i start using my phone nothing other than tha.t is it normal ?or any hardware realted issues ?it usually happens when i use facebook and open app store update or download apps when i close all and use just for text messages and calls its warm any suggestions what to do or just im worrying too much about it?