some times it can be your phone so
You are going to have to reset your iphone so please follow the following steps:
Plug your iphone into a computer ( most likely a macbook of any kind)
1. Hold down the home and sleep button at the same time.
2. When you see the apple logo keep holding in till you see the itunes logo and let go.
3. Then follow the directions on your computer to reset your iphone
Good Luck, Let me know if this helped you!!!