Based on the teachings in Chapter 19, what is the root cause of experiencing pleasure and pain?

Chapter 19 explains that the experience of pleasure and pain stems directly from our ego and identification with the physical self. The text posits that as long as there is an ego-consciousness regarding the body, intellect, mind, and life-force, the sense of being a "doer" and an "enjoyer" will persist. This perception of being the one who acts and experiences makes the feelings of pleasure and pain unavoidable. In essence, Chapter 19 teaches that our suffering is a consequence of the false bondage created by the ego, where we mistakenly believe "I am the body," while the Soul is actually distinct, pure, and changeless.