Have you recently upgraded to 4.2.2?
If yes, then do the following
1) Disable STAMINA MODE
3) Hold the power button for 7-8 seconds
4) Re-insert battery
5) Turn on the phone
6) Turn on the STAMINA MODE
This should solve your problem..
Nokia 5233 (At home)
Nokia 5230 (Broken Display)
Sony Xperia L (Stock 4.2.2, Rooted, ThunderZap 3.1-Lite)
Ex-Symbian Modder, new to Android world
Hit "THANKS" button, I appreciate it..