Why not a breast reduction? The only problem I would have with it is the scarring, and you'd think that creams or lasers out there could improve the scarred tissue in that case.
It's pretty much like it was hundreds of years ago; back then, women corseted the waist to achieve the extremely painful shape that was desired, or in Asia, women practiced foot-binding, which was plain torture. The only thing that's changed is our society is merely that there's more torture to choose from, a bit more variety

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Even though I'm a natal boy, I have scoliosis and lumbar lordosis, which makes it very painful to stand or walk for more than a couple hours, or bending for anything multiple times (I can't even touch my knees without bending them). It really sucks and feels so constricting. Sadly, there's really no cure, and constricting back-braces and bindings only help keep the posture straight....