If you charger has a light on it, notice if the light illuminates when you plug it into a wall. If not your charger may be bad, try swapping that charger out with a new one and try not to bend the charger as it will ultimately damage the cable connector indefinitely.
If you are using the same outlet, try switching to a different outlet
If that doesn't work you may have a bad battery on your hands and may need a new one.
If you have a multimeter and feel confident enough you can check both the contact points of the charger and the cable connector on the phone, the voltage should be roughly around the same amount of power, the charger being a little above than what is stated.
You may have to change your phones cable connector for the charging cord, has anything happened to your device recently?