In order to change the feelings of pleasure and blockage of pain, the endorphins must reduce activity in the thalamus and cerebral cortex. This occurs by the neuromodulators effecting the dopamine pathway by binding to a specific opiate receptor site. Products and theories have evolved, with hopes of opening the door to a totally new, incredibly profitable way of marketing concepts to control and eliminate pain, safely and legally. Despite modern technology, I believe that our bodies, without being chemically altered, knows best. Opiate receptors naturally occur in the body for a reason.
Pain exists and therefore the body needs to learn how to deal with it.
Hence, it adapted the structures in the certain sections of the brain that deal with pain. Pleasure is a desired thing amongst humans, the brain also adapts in order to utilize pleasing acts or feelings. I think it would be more beneficial to figure out how to best utilize what our bodies naturally give us. A perfect example of the human body taking care of itself is during childbirth. A woman goes through excruciating pain during labor and delivery, yet many women are able to experience all of the highs and lows without the aid of drugs.