I answered the other question and it is similar but different enough that I will give it a go in more simple terms. So nerves transmit messages using electrical current, more specifically the flow of sodium and potassium, but just remember that it's electricity. When you have any sort of cut or damage, our body recruits white blood cells that protect us from any bacteria that might enter. They also cause inflammation, this is to stop those bacteria spreading and warn the cells that they might get infected. It is also important that we feel pain, so we know something is wrong because we have the ability to do something about it. That's why inflammation causes pain. It does this by lowering our threshold so our nerves are more sensitive, or in other words it takes less damage or pressure or any other sense (heat etc) to cause our nerves to send the pain signal. Normally it is set higher, so we don't suffer too much pain. Naturally if you want clarification on anything just ask.