App doesn't process on device background xcode

i'm developing an iOS 7 App. The problem is happened only on Device.

At first time my app works in background.When there's an event, it is called in background. My problem happened lately when i test the app on background, it isn't triggered. So i have to enter foreground to make it triggered. I have turned on Background Modes (Background fetch & Remote Notification).

Does anyone have same problem with me ?