Pain is a symptom. Symptoms are the feedback that the body generates when it faces problems with its delicate internal balance (homeostasis). Without symptoms like pain, thirst, nausea and fevers, it would be very difficult for us to maintain a healthy body in the same way that it would be hard to drive a car safely with no dashboard display.
John is one of those rare gentlemen who has continued to play competitive soccer well into his late 50s. He is in really good shape, which you need to be to play football at that age—good shape except for his left leg. His left leg is not in good condition at all. In fact, once you get to know his left leg a bit better, it becomes apparent that it’s miraculous that he’s able to run at all, Let alone the type of running required to play competitive soccer against younger men.