[Panache]

Sorry to get all serious on ya, but could it be a keloid? Have you had your ear pierced? If so, sometimes the body reacts strangely to a wound such as a piercing, triggering excessive tissue growth, which can indeed be painful. If so, DON'T stick a pin in it, as that could make things worse. It's not a dangerous condition, but you'll need to see a doc.
This info comes courtesey of my med. student flatmate, so just don't assume either that I'm smart or that I'm right!