I have been facing a issue that my app doesnt run background for more than 10 mins , I have implemented background task which will fetch notifications instantly.
my appl
This is normal. You are not supposed to run timers in the background. On iOS7 and above, you should be using background fetch mode to fetch data (or do it properly, using push).
Read here for more information on iOS7 background modes.
Note, that on iOS7 and above, background tasks are even shorter (~30 seconds) rather than 10 minutes, so you are even less encouraged to use that API for such work.