Hi, you could try a hard reset from off to see if it works, will reset your phone back to as new condition so you would lose anything not backed up.
Performing a factory reset using hardware buttons
Press and hold the VOLUME DOWN button, and then press and hold the POWER button.
Wait for the screen with the three Android images to appear, and then release the POWER and VOLUME DOWN buttons.
Press VOLUME DOWN to select FACTORY RESET, and then press the POWER button.
If this doesn't sort it it may need to go for repair.