illustration (attribution, if any possible, is at the end of the article)
Regularly the Buddha is presented in caricatural manner, and people start denying that he suffered anything during the few decades he lived after attaining nirvāṇa.
Such a view could be seen with a sense of humour, if it didn't create unrealistic expectations and unreachable ideals (thus hindrances) for practitioners. Awakening is hard enough: views that make it "impossible standards" aren't helpful!
The Canon itself rejects such a view, both in relation to karmic fruits from earlier lives and in relation to non-karmic choices in his last life!
The death of the Buddha due to food poisoning is obviously not considered particularly blissful…
Or back pain is mentioned (but the commentaries point that it is not karmic, it isn't a consequence of an intention, it is merely a physical consequence of what was "appropriate" and had to be done to awaken and then to teach).
Overall, the difficulty lies with the caricature that nirvāṇa is intrinsically separate from saṃsāra.
The Pāḷi Canon is clear that attaining nirvāṇa doesn't make one suddenly immune to the unsatisfactoriness of the five aggregates, to the unsatisfactoriness of the worldly experience.
The Buddha warned explicitly against the caricatural view:
Monks, there are these two forms of the Unbinding property. Which two? The Unbinding property with fuel remaining [one attained nirvāṇa, stayed alive], and the Unbinding property with no fuel remaining [bodily death after/with the attainment of nirvāṇa].
And what is the Unbinding property with fuel remaining? There is the case where a monk is an arahant whose fermentations have ended, who has reached fulfillment, finished the task, laid down the burden, attained the true goal, ended the fetter of becoming, and is released through right gnosis. His five sense faculties still remain and, owing to their being intact, he is cognizant of the agreeable & the disagreeable, and is sensitive to pleasure & pain. His ending of passion, aversion, & delusion is termed the Unbinding property with fuel remaining.
— Itivuttaka 38 (tr. Thanissaro)
As long as an arahant lives, (s)he still experiences the five aggregates. The five aggregates no longer burn with the fires of lust, aversion, or ignorance… but they still burn with other fires (e.g. compassion and loving-kindness might provide motivation to live to help others: some fires —karma, tendencies— may be wholesome)!
And as long as they burn, the five aggregates are impermanent and unsatisfactory (e.g. the arahant continues ageing, one doesn't suddenly escape the karma of being born human… or e.g. the arahant might teach but not always convince — (s)he won't get upset about it, but that doesn't mean 'ageing' or 'speech' magically became "satisfactory" or "reliable").
The value of the liberation from pain (from lust —e.g. asceticism— and from aversion –e.g. constantly seeking protection or separation from it) lies in one's ability to act without biases induced by pain, without prejudices about pain, without preconceptions around pain…
It lies in one's ability to choose one's life, and not let pain steal this choice away.
It also lies in the ability to die in peace (without lust or aversion towards death — lust e.g. to end some pain, or aversion e.g. from the pain of leaving people behind, who will suffer from the separation and grieve…).
The value of liberation from pain lies in one's ability to do what's appropriate regardless of pain.
And there is true bliss in experiencing these appropriate intention and appropriate action.
The caricatural, ordinary mind rejects this idea that bliss might come with pain, stuck as it is with black&white "right vs. wrong" projections, but the ordinary mind isn't the awakened mind.
The enlightened mind often doesn't interpret as 'pain' what the ordinary mind labels thus: the awakened mind might interpret the phenomenon as e.g. "right effort". The awakened mind relates differently to the phenomenon and does experience bliss, but it's not some naïve version of life in paradise where everything is easy and where one lives among awakened beings (none of them ignorant, none of them suffering, none of them acting unwisely…).
Liberation from suffering is not found in some idealised painless world, nor in some paradise, nor even in some meditative state (in which consciousness ignores the other aggregates, e.g. thanks to concentrating on some fixed object).
It is found in a world where pain becomes irrelevant to one's intentions, where pain doesn't stop one from wholesomely contributing to the world, where pain is overcome —one way or another, not always in the initially-anticipated way— for the benefit of all.
It is found in a different way to relate to what the ordinary mind would call 'pain', not in some magical (or chemically-induced) absence of pain.
It starts with neither blaming oneself as a victim ("I must have deserved this pain, I must be a bad person or have a bad karma") nor blaming others as victims ("(s)he must have deserved this"). It starts with not taking pain 'personally'.
It continues with appropriating lessons (about causality, not about the 'worth' of 'persons') and then using these lessons to wisely respond (nurturing the causes of wholesome effects, weeding out the causes of unwholesome effects). Think prevention: in relation to victims, the causes to address are often those tied to the perpetrators, not those tied to the victims… but one may also want to make sure that victims don't draw the wrong conclusions (and e.g. end up living in fear, in shame or in disgust, potentially by interpreting past events 'personally').
It goes on with appreciating one's contributions to a better world. Even if one suffered (as a victim… or as a repentant perpetrator), once the pain is overcome, what's left after turning the pain into a wholesome contribution is the appreciation of how it is now less likely for anyone to suffer the same.
Liberation from pain is not in sainthood or martyrdom (which leads to dissatisfaction… because one can never do enough to fully protect all sentient beings from all future hurt). It lies in appreciating how we turn past pain into wholesome contributions, it lies in appreciating how we end up constructively relating to pain instead of limiting ourselves by it. Appreciation here&now is an appreciation of 'small' or 'partial' steps!
The Buddha did not take his anguish of death 'personally', or as a sign of personal failure or bad karma. He did not enter into depression either; instead, he looked for the causes of unsatisfactoriness, stepping away from questions of 'persons' and enquiring into 'tendencies' and 'causality' directly. He thus turned his anguish into a constructive attitude. Once awakened, he could appreciate that he turned his unsatisfactoriness into useful teachings, and that some people achieved liberation thanks to such teachings. He needed not regret that he still experienced back pain in a human body or that only a few were 'quickly' liberated thanks to the path he taught: not letting pain choose one's life, turning dissatisfaction into a positive contribution, and appreciating partial steps, an appropriate response to the situation at hand!
Naturally, it's easier to appreciate one's contributions to the world if one drops self-obsession, if one realises selflessness: "I want this, I don't want that" isn't freedom from pain, it's the cause of it! It's easier to contribute if one doesn't blindly ignore the pain of others. It's easier to appreciate one's contributions to the world if one can sympathetically rejoice when others benefit, when others cease suffering, when others rejoice! After accepting reality (as it is, no matter how 'unsatisfactory' it is judged) as the context which one will contribute to, the most "wholesome" intentions will be those directed "for the (direct and indirect) benefit of all".
image: "meditation" by © Ilisa M. Millermoon, purchasable via fineartamerica.com/products/meditation-ilisa-millermoon-greeting-card.html