iPhone heat and battery drain In december 2013 I bought an iPhone 5s. A couple of weeks ago I restored my iPhone to 7.1.1 using a back-up on my Mac. Since then, the battery drains very quickly and the devices heats up most of the times even though the device isn't under heavy load.

Things I tried to resolve this:


Restoring the iPhone to factory defaults using iTunes with the original ISPW file (and later using the device itself)
Turned off iCloud, Mobile data, Background refresh and even turned on Airplane mode.
Resetting the device by holding the power and home buttons for a couple of seconds.
Recalibrating the battery (100%-0% and back to 100% again in one time)
Sending the iPhone to Apple, they replaced the battery but haven't tested anything since the problem is still here.


Symtomps:


Using the iPhone for 15 minutes will drain the battery ~20%.
Device gets hot sometimes even when I'm just reading an e-mail or responding to a text (so no gaming or intensive Apps that would trigger higher CPU load).


Log:

I connected my iPhone to xcode's console to log some things this is what happens every 30 seconds or so:

Jun 11 22:17:46 Tims-iPhone mstreamd[345] &lt;Notice&gt;: (Note ) PS: Media stream daemon stopping.
Jun 11 22:17:46 Tims-iPhone mstreamd[345] &lt;Notice&gt;: (Note ) AS: &lt;MSIOSAlbumSharingDaemon: 0x146d69e50&gt;: Shared Streams daemon has shut down.
Jun 11 22:17:46 Tims-iPhone mstreamd[345] &lt;Notice&gt;: (Warn ) mstreamd: mstreamd shutting down.
Jun 11 22:17:46 Tims-iPhone mstreamd[346] &lt;Notice&gt;: (Note ) mstreamd: mstreamd starting up.
Jun 11 22:17:46 Tims-iPhone mstreamd[346] &lt;Notice&gt;: (Note ) PS: Media stream daemon starting...


I think that something is triggering the iPhone's CPU since the devices gets hot too.
Is there a way to find out what is draining my battery or should I send the iPhone back to Apple (again..)?
This happened to my 5S as well. It had a light spot on the screen and it was separating from the casing as well. 

I'd suggest bringing it to the apple store to have them check it out. They should run diagnostics on it and determine if it is a battery issue. When I brought mine in, the diagnostics came back ok, but they still offered to replace my phone in its entirety for $79 (the price of the battery). 

Since then, my new phone has worked perfectly, so hopefully that is the case for you.