That is a big question that many people have, that also many «spiritual» leaders claim to be able to answer, but, I am somewhat responsible for clarifying these sorts of things in its FULL «Context» wherein such «Truth(s)» would otherwise be «lost» or not be available to Truth-Seekers.
Whilst, yes, many have indeed _technically_ «chosen» to be here, here in this universe or here in this earth-life or both, some people have this idea that we also «chose» to «suffer» which may «technically» be true, but, has been lacking in context that I will re-clarify herein as follows...
What many came here for is analogous to learning that a number of your friends or other «adventurers» have gone into a cave... only to have never come out; or if anybody did come out, they warned everyone else of its terrible nature, not wanting to return; everyone else, knowing that the sole-survivor(s) is/are clearly traumatised, have not yet any idea what such «traumatic-experiences» are or could feel like, but, also know that such trauma is keeping many of those who had gone into the cave before them into a «trapped» state that is keeping them from being able to come out.
When you come to this earth or if you are like the even much fewer like me who came to this universe from outside of it altogether, entering into this sort of like is a lot like going into a cave wherein you know that many people have never returned from, knowing that, yes, you are putting yourself at great risk of getting «trapped» yourself, and, even potentially experiencing the «trauma» and «suffering» that the «survivor(s)» may have warned you about, yet, you want to «save» the «stuck» people/adventurers anyway; in this analogy, yes, you did indeed «choose» to come here into this «cave» (metaphorically), and, yes, you did indeed even choose to risk experiencing «suffering» (and trauma), a process which is one of the only ways in which one can «consciously relate» to those who are in fact «trapped» here and «suffering» because of it as a result, with the idea/theory/hypothesis that it would make you better-equipped to be able to relate to them and thus understand them and have empathy for them and ultimately be able to assist them...once you «over-came the "sin" (loosh)» within you that all of us become contaminated with when entering this metaphorical-cave.
And, remember, NOBODY who is «sane» CHOOSES to «live a life of SUFFERING» and, from my perspective, does come across as something of a «gas-lighting deception» that is part of the psychological-trap-system that tries to tell you that «you chose your own suffering» when in reality, just like not having a conscious-understanding of the traps and dangers of going into a cave where nobody (or very few) people have ever returned from, similarly, if you KNOW that it HURTS LIKE HELL to get your bones broken because you intentionally allowed some sort of large rock to fall onto your limbs before, but, were restored back into a whole body, with the memories of it intact, then, I can rest-assure you, WITH the «consciousness-knowledge» of the «suffering» that is involved with letting the rock fall onto your limbs, you would definitely NOT choose to self-inflict such «suffering» upon yourself unless you're some sort of «insane» masochist which you would know that you aren't if you are sick and tired and fed up with being «forced» to deal with all or any of life's «suffering» experiences...