Do we know the neurobiology of pain, if so what is it?

Factual Questions
1

Do we know anything about the biology of pain (both physical and emotional)? If we do, is pain caused by an excess of some neurochemical or a deprivation of it or is it much more complex than that?

If you take someone going through heroin withdrawl, there is emotional pain. But this emotional pain seems to be due to a lack of opoids to meet the requirements of the extra endorphin receptors. So is the emotional pain of heroin withdrawl due to an excess of some neurochemical (as a result of the lack of endorphins) or is it due to just a lack of neurochemicals?

The emotional pain of depression is due in part to a lack of neurochemicals like serotonin, phenylethylamine, dopamine or norepinephrine. There are drugs that boost serotonin levels in a variety of ways (SSRIs that put more serotonin in the synapse, B vitamins that make the enzymes that make serotonin more effective, 5htp or tryptophan that are building blocks of serotonin, etc), and these seem effective for treating the emotional pain of depression. Most depression cures seem to be based on making more neurotransmitters (both alternative treatments and prescription treatments). Most everything except ECT and therapy seem based on the idea of making more of the neurochemicals I listed above.

So are there pathways in the nervous system which are activated strictly to cause emotional and/or physical pain or are these feelings caused by a lack of proper activation along neural pathways?

2

This isn’t exactly what you’re talking about, but we do know that an enzyme called COX makes chemicals called prostaglandins from cell membrane components, and these prostaglandins are important in pain production. Apsirin, Tylenol - all those over-the-counter analgesics all inhibit COX. More recently, it was discovered that there are actually two COX enzymes, and COX-2 inhibitors have become important prescription pain relievers.