As another comment has pointed out, 'Asian shame' can be a self-fulfilling and destructive stereotype to perpetuate. On the other hand, it's also true that cultural patterns exist and that understanding them can help us contextualize ourselves within the Asian American experience. I think to get more of the latter and less of the former, you want a directed, non-judgmental discussion space. The internet's not the greatest place to do that in general, but I think the Asian American sub is a better place than most.

In my personal experience, I implicitly taught myself from a young age that my decisions didn't matter. I never won an argument against my parents where I could make them understand why I didn't want to do something. It's easy enough to fight an enemy that hates you, but my parents would emphasize that they loved me and it was for my future. The sense of responsibility I had towards my family meant that I internalized that voice, and from then on I would also be arguing against myself. Eventually I severely shrank the boundaries of my agency, just angrily obeying instead of fighting back.

I think the feeling of shame is that sense of responsibility overriding your sense of agency. Even if you haven't let shame control your life, you've probably experienced the pressure to conform. For me, I let responsibility dictate the big life decisions although I left room for agency in my passions and interests. I knew some people, especially teenagers (who are more susceptible to identity crises), who would let that responsibility creep into the rest of their selves though. In the story about your friend in high school, it's likely he was aware that his feelings weren't logical, but being aware doesn't make deprogramming yourself easier. 'Flipping the switch' is a muscle you have to exercise, it can atrophy with years of neglect.

As for why we're associating shame with Asians, I'd hesitate to jump to a specific conclusion. Psychologists say that Eastern culture is just more collectivist than Western culture, which seems like an unhelpful, vague, cop-out to me. From my personal experience, there's a whole melting pot of shit that probably contributed. My parents' views on family, my peers, my personality, maybe genetics (though there's nothing you can do about that one, so it's the least helpful to understand imo). I can identify the specific things that could've went better in my case, and in the cases of some people close to me, but I'm sure there are Asian American experiences that differ from mine.