Are you power buttons, mute toggle switch, and volume buttons not working correctly. Overtime wear and tear can cause these buttons to stop working on your iPhone. The headphone flex cable which is responsible for the functionality of the volume button, power button, mute toggle switch, and the headphone jack.
Have this cable replaced and restore life to these crucial buttons.
Force Quit
Applications that you run unstable? Close forcible application simply by pressing the Home button for about 6 seconds.