How am I able to fix my phone when it's not charging?

@sammiekins123 since you already checked the most common parts, replace the battery next. That way you have a known-good starting point should further troubleshooting be necessary. If that does not work, the you will have to take your phone apart. Check to see if the USB port is still properly connected and measure the voltage on the plug end with the charger plugged into the phone. Also , check the voltage on the battery connector with the phone plugged into the charge. Let us know what that voltage is.