Overheating While Screen Locked I have a Nexus 5 running stock Lollipop and lately I have noticed that when I lock the screen, but leave an app (or multiple apps) open (e.g. Chrome, Facebook, Youtube) the phone gets very hot and the battery drains like crazy. It's like the phone is acting as if the screen is still on.

Has anyone encountered this problem? Can anyone suggest a solution?
I had similar kind of issue with initial Lollipop version 5.0. I had clean master installed in my phone which showed that nearly 60-70% of RAM and CPU usage even though no apps were running, which end up heating my phone. 

When checked in Settings-->Apps-->Running application mostly were services from android os. But they have now improved it in newer version of lollipop...currently my phone has version 5.1.1. In this it drop from 60-70% to 40% RAM and CPU usage.

Also lollipop has lot of bugs you can find a consolidated list here - https://www.androidpit.com/android-5-0-lollipop-problems-and-solutions