There are series of ways that you can handle this kind of issues which is your phone getting hot while it is charging and the device finding it hard to boot on. They are:
1. Leave your phone while charging: I am saying this from experience as many of us have developed that attitude of always checking on our phones when it is charging and that is something that can make your phone to feel hot when it is being charged. When the phone is charging, don't be tempted to operate it for any reason whatsoever as this may be a heavy burden on the mobile device.
2. Uninstall apps: If your phone is being affected by too many apps that are eating up some space on the phone, it may bring about the phone failing to boot on when you want. So, it is advised to check the apps on your apps and uninstall the ones that you are not making use of.