This is a form of Buddhist meditation called Tonglen. Tonglen helps you develop compassion. It helps you develop capacity and willingness to feel another person's suffering as well as our own pain. If you can't feel it, you can't heal it.
For example, if you see a hurting person, breathe in their pain, their worries, their fear. Take it into yourself, but then let it go and send them love, peace, joy--whatever might heal their heart. This is what Tonglen is. It's a simple process.
Try it sometime. Breathe in pain for all of us, and breathe out love and healing for all of us. You might find yourself healing your own heart and mind by just breathing.