Thanks for the detailed feedback, @erh.germany. Did you know some of the medical officers asked patients to cough while they were giving them injections? The moment they cough, the doctor would stick the needle in and the patient won't feel a thing. It seems, our mind can be too preoccupied with task hence ignore pain. It's like a cut, if you didn't realize it while doing something interesting, you won't feel it but once you see it, with your own eyes, you started to feel pain. It's interesting, isn't it?