Here is the strange thing. Pain is supposed to be a perception of an experience. I will be dammed if banging my head against a table and the resultant experience I have is just perception. However, scientists believe that pain is the defence mechanism that your body adopts to tell you to stop doing what ever it is that just caused you pain, a warning sign if you may. Pain manifests in many different ways and your sensory system has to be capable of differentiation between the light touch of your dad’s hand on your head and the hard punch of Mary Kom (multiple Olympic medal winner).
Your skin has sensors that have been designed to feel different experiences. Depending on how you fancy spending your Monday afternoon, it is capable of knowing the difference from light touch to deep pressure. You also have special pain receptors called nociceptors that can differentiate a serious injury such as the breaking of your skin or deep indentations. These get fired to make you jump back or up or around, what ever your hand-picked articulation of pain. This dance (no not the dance, but the pain sensation) is interpreted by the spine to create an appropriate response. The sensation still travels to the brain to allow you to form a deeper impression of what the heck just happened. This includes an understanding of the experience, forming of memories, creating associations between the hand that punched you and the pain you probably felt et al.
The sensation then travels to the thalamus region of your brain where is it compared with prior experiences that categorise the level of danger. Should you punch Mary back or just run away, tail between your legs. All these choices are exercised by the thalamus. Finally this signals your limbic system which determines your emotional response. Should you cry or put on a brave face or grimace? All of this just for spending your time picking on Mary? Really, shouldn’t you be more careful in choosing who you decide to heckle?