Hi, I'm Randy. Welcome to JustAnswer. I'm reviewing your question now, and will post back with your reply ASAP.
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 a faulty charger or bad battery. Since you tried the reset that was suggested to you how long has it been on the charger?