Hi, try booting your device into safe mode -
https://support.t-mobile.com/docs/DOC-5744 (these instructions are universal to Android so don't worry about the fact it says s4)
If the phone powers up and has zero issues this means a 3rd party app you have installed is causing you issues. Unfortunately there isn't a quick way to find out what app it is, but at least you can begin to uninstall apps one by one until the problem persists.
Failing that a good old factory reset would be my next advice. This will reset your device to what it was like when you first bought it. Just make sure you back up all your data / media as you will loose these when performing a reset.
Good luck
