Have you tried performing a hard reset on your phone?
Be aware that a hard reset will erase all your user data and downloaded apps. It will restore your phone to a factory default condition. It will be like when you first bought.
Before your perform a hard reset:
1. Perform a backup of the phone using the phone's backup feature.
2. Ensure that the battery is fully charged.
3. Do not leave the charger connected when you perform a hard reset.
4. Remove the external SD Card (if installed).
Here is a link that shows the two methods available to perform a hard reset.
Be patient it takes a little while to complete a hard reset.
Once the hard reset is completed, turn on the phone and see if it has resolved your problem.
(It may be best to always turn off the phone if you want to remove/insert SIM cards).
If everything works to your satisfaction, restore the phone from the backup that you made before, using the phone's restore feature and see if it is still working correctly.