Physical pain.

When living under a lot of stress, you feel physical pain. The pain is not conceptual but acute concrete damage on the body.

When I feel stress, I try to run more. On the day I felt more pain, I try to run a longer distance. I think this is a healthy way to struggle with the pain and stress. Somebody says that "Pain is inevitable, but suffering is optional". I cannot avoid this pain, but I do not want to suffer myself anymore. Someday, I wish I could be strong enough to walk the lonely way alone.