Hi, my name is ***** ***** certified professional with over 10 years experience. I will be glad to try and assist you with this. I am sorry this happened. This could be a glitch in the software and the iPhone needs to reboot, lets try and force a reboot > Hold the home button and the power button down for about 30 seconds or until the Apple logo appears on the screen, then release both buttons.
It could be an app or just that the firmware gets glitches. It is similar to a computer, the only thing to do is the hard reset. If it continues you can do a factory restore and do not load any other apps and seer if it corrects the issue. If it works normally after the restore them you can add any additional apps that you use one at a time and each time you add an app wait to see if the issue returns before adding the next app.
The process for restoring an iPhone begins by wiping the iPhone, which puts it into the same clean state it was when you first got it out of the box. But before you take this step, you must make sure your iPhone has been backed up to the iCloud.
You can verify your iCloud backup by going into the iPhones settings and choosing iCloud from the menu. In the iCloud settings, choose Storage and Backup. This will take you to a screen that will display the last time the iPhone was backed up to iCloud.
Once you verify the backup, you are ready to begin the process. You will start by erasing all data and settings from the iPhone, which puts it into a clean state, Go to General from . Scroll all the way down the General settings until you see "Reset". From this menu, choose "Erase All Content and Settings".
Once this complete, go through the set up and then choose to restore from a backup, you will be taken to a screen where you can choose from your last backup