Chiron isn't a planet. It's a small icy body, a centaur, whose orbit runs between Saturn and Uranus and takes about fifty years to complete. It was discovered in 1977 and named for the wise, wounded centaur of Greek myth, who taught healers and heroes but could never heal himself.
Astrologically it's read as the wounded healer: the place in a chart where a person carries an old, tender hurt, often tied to feeling inadequate, left out or not enough. Its sign and house show where that sensitivity sits. The same place tends to become a source of unusual understanding, so people often end up helping others with exactly the thing they found hardest themselves.
It isn't a problem to be solved. The wound rarely disappears; what changes is how much of it is carried alone. Chiron moves unevenly, spending anywhere from about a year and a half to about eight years in a single sign, so its sign tends to mark a generation, while its house and aspects make it personal.