Extension cord makes my charger hot?

Why does the indoor extension chord make my phone charger hot? It's an iPhone 6 charger. Whenever I have it plugged in the extension cord it gets hot to the point it's burning hot to the touch. I've tried changing chargers and extension chords but it still does this.

You have a problem here. The charger for an iphone or any electronic device should work so efficiently that there would be no discernible heat build up. Sometimes the battery itself may get hot on charging, that is because a partially charged battery has considerable internal resistance so passing a high current through it generates heat. That would be normal. But the external charger using switch mode conversion should never get warm. The only time an extension cord should get warm is when you have plugged a hot device into it and heat from the device is conducted by the copper wiring. This is why you never plug a room heater into a normal extension cord.

Hi it is not just the extension cord it is the Phone charger that is the issue here as it is a switch mode power supply.

There's no reason that would happen, an extension cord is just wire, it doesn't do anything to the voltage. The one thing I can think of is that when you have the charger plugged into the extension maybe it is in a different orientation which is allowing heat to build up inside it, but even so, as lare said, it should never get so hot.