Nobody wants to experience pain.
Once you have it, you want to get rid of it as quickly as possible.
When we live with pain for a long time, it can change our sense of "who we are." It changes the way we see the world and how we relate to it. 
We often don't have good answers as to why we are in pain or what to do about it, which makes it even harder.
Pain is invisible, but it can affect every aspect of our lives.