Why are bra's made to be so suffocating?

Whenever I go out, I wear a wired bra, but by the end of the day, I'm suffocating a little. I noticed that after taking my bra off I could suddenly breath. I don't think there is anything wrong with the fit of my bra because it feels comfortable putting on at first, but after a long while, it becomes uncomfortable. Now, I just go braless and use something else to cover up the front of my breasts without having to show my nipples. Why are bra's made to make me suffocate and uncomfortable. I've also tried multiple other bra sizes to test if it really is my bra that makes me suffocate.
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I want everyone to know that I try on multiple bra sizes to know if it was the fit of the bra that is causing my discomfort, but it was not. I am a 34A and have tried from 34B's to 36A's. They were either too big or too small, but mostly too big. 34A's are where I'm genuinely the MOST comfortable at, but after a while it gets uncomfortable.
Why are bra's made to be so suffocating?
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