PAIN, FEAR, JEALOUSLY ARE ALL MESSENGERS...NOT EVIL

If a thorn strikes your feet, and it pains,....what do you do? Do you try to get rid of the pain or rid of the thorn? Dont you use the pain as a tracking signal to track where exactly is the thorn? Didnt you know because if the pain that a thorn has inserted your flesh in the first place...a place where it shouldnt be? So didnt the pain act like an alerting system in the first place?