Why when inflicting pain on yourself it doesn't hurt as bad as when someone else is inflicting the pain on u?

Question

I have always wondered this. That I can dig a splinter out or rub a hurt muscle as hard as possible and it doesn't hurt that bad. But once someone else is doing it to me the pain intensifies. Why is that? Why does it hurt worse when someone else is doing it rather then yourself?

Answer 1

Probably because you are aware of every move you make. You determine how hard you are going to pinch yourself, smack yourself, whatever.

When someone else does it you don't know what to expect.