F. Is pain subjective?
Pain when felt is not subjective. This is simply a charged atomic weight difference in any living cell/cluster/group of cells.
What is subjective is how much of the difference is the threshold for a brain to start worrying about the same. Again subjectivity is a quantified element and the ratio of pre-frontal cortex to Amygdala absolute electric potential+neuroplasticity differentials.
Mental pain is essentially emotional pain, which is essentially a point that is fearful(not threatening). Fear is a predictive mechanism of the brain. Any predictive neuropathways are weird from the 4th week of the pregnancy, or at least 8 months before anyone was born. So, how a brain perceives a situation as a potential threat to the future is beyond one’s control or training.
Fear is again processed in the subconscious. Avoidance is a mechanism of inhibiting the pathway from awareness to the subconscious, or cortex–x–medulla. Any neuro blockage is done by closing the path with CaO2. So, essentially pain avoidance will increase Ca++ in the body, raising blood pressure.
A calcium channel blocker will simply increase Na+Cl- breakup, to supply the needed charge, creating HCl and making the body Acidic. Avoid pain, get acidic or hypertensive.