Suffering is to experience something that one does not want to experience.
Distress at a physical injury, disease, aches and pains, is suffering.
To want to get out of a circumstance is suffering. To want something and not be able to get it is suffering.
Suffering can be experienced as bodily pain, a cognitive disapproval of a situation, or as an affective/chemical response in the brain.
It is easy to comprehend that bodily pain is essential to avoid fatal harm to the body. Pain is body's way of seeking attention.
It is also easy to comprehend that cognitive disapproval is impossible to avoid as long as one is a discriminating individual. To have values and judgments is to inevitably approve and disapprove. You may say that you don't judge, but you do. Without choosing, life cannot sustain itself. Nourishment is born of choice.
A crude form of valuation and judging to propel behavior is also built-in into our affective pathways. To hear one's child crying, a mother feels distressed and that distress is an affective push for her to do something. All affective pain has evolutionary origins as providing a survival advantage for the genes.
Given the rapid advances in thought and applied thought, many think that affective responses are obsolete and even counter-productive in certain situations. Probably.
There is a fringe which thinks that it is obsolete and counter-productive in all situations. That is possible, if you are on welfare. More ahead.
Is it possible to completely do away with affective pain and live only with physical pain and cognitive discrimination as our tools? What is distinctive about affective pain that one is willing to accept the other two forms of suffering, but not this?
Is there a distinction?
Cognitive discrimination is impossible to avoid. Death is inevitable otherwise. Those who say that they do not judge and accept everything are liars.
Physical pain is impossible to avoid as well. You cannot control the transmission of bodily distress signals except by usage of analgesics or anesthetics.
However, affective pain is a choice in many cases. For example, the feeling of guilt is a choice that one can avoid if one gives up the force of conscience. The feeling of missing one's loved one is a choice that one can avoid if one does not love in the first place. It may be possible to cultivate the neo-cortex so much that some affective pathways wither away. It is quite common on Wall Street.
Affective response is also crude in nature. Its effects outlast the event, and they are sometimes far more than what the event required.
To not get overwhelmed by, or not have some kinds of, affective responses is what is considered maturity, modernity, literacy, etc. The progress of man is the obsolescence of certain affective responses. If you see a potential rapist coming towards you, do not get agitated and scream, just go into a store and dial 9-1-1. If your kid is crying due to loud noises upstairs, do not get distressed, you know (your doctor has told you) that it is normal.
Affective responses are a survival strategy for the genes. To want to be rid of affective suffering is a desire for more cognitive control. For more autonomy, rationality, choice, knowledge, structure, formalism...
As it becomes safer and possible to be more and more rational, many affective reactions will naturally go extinct. As an example, dread is pretty uncommon in a normal, healthy human being in an urban setting. Pining for one's mother is becoming quite rare in certain areas of Manhattan.
The reason pure rationality does not always work everywhere (it leads to dysfunction if taken to an extreme) is because the neo-cortex, and the institutional support, is not yet advanced enough to handle all the challenges effectively and still allow the carrying human being to thrive. As long as an irrational man can make more money in the stock market and lands more women than a completely rational man, the completely rational man may be happy, but his genes are at a disadvantage and his happiness is therefore written on sand. The men who thrive best are those who are able to use their passions (fears, desires) to drive them towards their ends with their rationality helping them as the means.
Even memetic propagation is driven best by ideological or religious fervor.
A man who rejects the whole of passionate/biological push/pull mechanism may have better brain states moment to moment, but is doomed genetically and ideologically.
Suffering is an evolutionary trait of humanity. It serves a purpose. It has a history. It drives people towards useful genetic goals. It is a form of intelligence (though a crude one). As long as suffering is needed, it will be there. When suffering becomes genetically counter-productive, you won't need evangelists to preach happiness.
Aldous Huxley said: "The ends are ape-chosen, only the means are man's." He was right, of course. The problem is if you ideologically disapprove of this state of affairs. That is, if you think of the "ape-chosen ends" as somehow "lesser" ends than some other ends. It is another matter that quite a few people are disapproving of the man's means as well. "Don't be an animal, don't be an intellectual."
All self-help (including spirituality) aims at the reduction and possible ending of affective suffering. In that state of sociobiological disadvantage and dysfunction, you can either have people take care of you (fans or disciples or acolytes), or be in a welfare economy (others pay for you), or live off your earnings made as an ape, or die. If you are enlightened, or otherwise consider yourself as higher than an ape, you know what tricks you pull off to get by.
Suffering is not the nightmare that you think it is. It is understandably glitzy to pursue the famed end of suffering ("Glory!") at the risk of dysfunction ("the real world sucks anyway"), but consider, pause, take a deep breath. If you are truly honest, you will reject everything in your journey. But then, what will you live for?
Do not reject your suffering, for in the absence of ape's ends (which include selfishness and altruism both), and which ends cause you to desire and suffer, you have no ends. None. Let that sink in.
The desire to be completely rid of suffering is a death-wish.
The corollary is, of course, that if you are claiming to be completely free from suffering, and are still living, you are supremely deluded.