Pain is so heavy it hurts, and the more it hurts the heavier it makes everything else. Pain and suffering steals clarity and drains our faith, and it's the biggest challenge many of us will face. It can also raise our biggest questions about God and life, but God is at work in all of our painful circumstances to draw good out of the bad.
Lots of different things can lead to our hearts becoming hardened. It is something that can happen to all of us. You can tell when it starts to happen because you become less patient and more apathetic. Jesus knows what your heart needs and He is on the full send to get your heart back to where it belongs.