To soft reset (turn off, but dont delete data stored on the phone) your iPhone or iPad,
- Press and hold the Sleep button.
- Press and hold the Home button.
- Hold both buttons until the screen turns off, and then turns back on.
This is a common practice used as a first step in many troubleshooting tutorials
Another thing you can try is to reset your settings. To do that, go to
- Tap General
- Tap Reset
- Tap ‘Reset All Settings’