When transiting Chiron, the asteroid that marks an old wound, forms a square to your natal Sun, the planet that represents your core self and where you shine, those two things come into direct friction. A square is two points 90 degrees apart, two needs that will not sit comfortably in the same day. The wound and the self are not ignoring each other anymore. This transit tends to last several months to more than a year, and I see it turn up on people's charts at some of the more uncomfortable but clarifying stretches of their lives.
The Sun is what you run on. When you are most yourself, most alive, most recognisably you, that is the Sun doing its job. Chiron is where that gets complicated. A square between them does not break the Sun; it puts the wound somewhere the Sun cannot avoid.