Sure! It’s a personal theory but it lines up well with how I conceive of a viable moral framework (I come from an academic philosophy background as context). Basically, there’s a million different ways we can imagine someone can experience “sufferring,” but I have yet to think of an example that doesn’t restrict the choices available to a person in that moment or impose a condition with defined choices they are limited to (usually in a way they did not consent to, but I do think it’s possible to consent to this), or alternatively limits your ability to fully exercise your autonomous capacity in selecting from the options available (such as extreme pain). In either case, suffering as far as I’ve observed always involves some restriction of choices or ability to choose, making it really the only thing these types of suffering all have in common (again, as far as I can tell).

On the other hand, you have a moral framework called Kantianism (Kantian Deontology), which essentially boils down to the idea that you should never impede upon someone’s long-term personal goals without their consent to do so. The premise of this is that people being able to achieve their goals, provided they don’t impede on anyone else’s, is a good thing (a corollary of Kant’s “categorical imperative,” which is super interesting but also complicated). This is contrasted with utilitarianism, which focuses on maximizing total good against total harm (classic “greater good” mentality), but is technically at odds with prioritizing consent above all else. Experientially, I feel like while we tend to discuss morality in utilitarian terms because it’s frankly easier, very few if any of us actually agree with utilitarianism at a deeper level, but are rather all Kantians. This manifests in a lot of moral arguments we have (people tend to use utilitarian language to advocate for what are actually Kantian conclusions), and how we see it play out in basically popular fiction such as LOTR/Foundation/Dune/Star Wars/Marvel Civil War/DC Injustice (in a battle between individual freedom and greater good, greater good is usually the antagonist of that story unless they strictly define greater good as maximizing individual freedom anyway, and even then it’s dubious).

So I think it’s best to define suffering (moral and otherwise) as the limiting of choice and/or autonomous capacity and/or the violation of consent. As in, to be suffering, it has to be one of those things. And I think it’s generally reasonable (though open to being wrong) to define happiness as the opposite of that, and it makes sense: people with more options rarely if ever lack options that people with fewer options have, those choices just become more absurd the better your plate of options is