Chiron is a minor asteroid that was named in 1977. Since that time, it has been more often ignored than not. It turns, out, however, to be a highly important piece to understand in a natal chart. If the rest of the chart is like a pane of glass, Chiron is where that pane is broken. It is the wound that refuses to heal, consistent with the mythology of the centaur. A better way of understanding it is that it is where a person must really dig into their connection with spirit and be willing to do whatever the sign symbolizes in the service of spirit without any specific kind of expectation. If the ego enters into this area instead of spiritual service, it results in a wound and then the myth of Chiron begins to cement itself into reality. Physical issues are not far behind.
In short, Chiron is where a person might want things quite badly to go their way, but instead the area refuses to do so. "You don't always get what you want, but if you try sometimes you might find you get what you need" applies here.