I understand your conscious thinking about pain, and wondering about pressure points.
I did uke for many of the rougher techniques for my karate teachers because of my ability to endure pain, and recover ... so I know what you are thinking in this arena.
Simple put, do you react to wrist twists, arm bars, other manipulations, and feel some type of pain? Unless you have dead nerve endings, the answer is yes for living human beings.
You feel pain because of nerve endings, or pressure points.
Even if you were drugged up, your body would recieve these signals to the brain until either unconsciousness would occur, or serious injury. If you have never been knocked out, then I guess you don't know the involuntary feeling of body shutdown to protect the living organism. Signals sent through nerve endings signifying pain ... also called, pressure points.
Poke about your arm, gently, until you find the most pain with angle and direction, when you do. that is a pressure point. They abound in Aikido practice, otherwise many techniques would not work.
Have fun finding them, and practicing Aikido.