Share your experience!
Hi and welcome to the community! Since you're new please be sure that you have checked out our Discussion guidelines.
I would suggest that you try to boot your phone into safe mode to see if the behavior may be related to any 3rd party app that you have installed in your phone:
http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008
If you experience the same behavior in safe mode, I would suggest that you have your phone examined by a service center. Please contact your local Xperia support team for more information:

@KT,
Try to repair the phone using Sony Update Service to make sure whether it is a software or hardware issue.
Cheers.
SONY SUPPORT please help :--
http://talk.sonymobile.com/t5/Xperia-L/Problems-after-updating-to-15-3-A-0-260/m-p/475281
As only Camera Flash problem remains in my phone , so im shifting to this topic :-
I was wondering that the xperia L Camera flash isnt working maybe cause of the kernel ...... so if i root it , unlock the boot loader and flash a kernel ... would it sort the problem .... ??? what's your take on this ...
Please help!!!!
Best Regards
Ranjan