Listening to loud music can damage your ears, but not in the way of making them painful. You've got one of two things, either you have a small spot in your ear which will go away on its own after a few days, or alternatively you may have an ear infection, in which case you will probably need to go to the doctors for some ear drops/antibiotics. Give it a few days, if it is an ear infection it will get worse, if it isn't getting any worse then it is unlikely to be an ear infection and will clear up on its own. Either way, it's nothing to worry about.