Originally Posted by Mr. Lucky
OP, I notice the Clean Master icon in your notification bar. If you are using the task killer (or "1 Tap Boost") feature of that app, it could very well be the cause of your issue. Task killers are totally unnecessary in recent versions of Android, and cause drain by constantly killing off system processes that automatically restart themselves.
Killers may have been unnecessary in any version of Android, but they are clearly unnecessary in a phone with 2GB of ram.
I think we may have discovered the cause.