>>76384038 (OP)It is obviously massively genetic and due to how your bones have grown, but can be improved to a degree.
You need to step belly breathing and "putting your shoulders back" thinking this is good posture. Your posture should focus and getting your ribs in line with abs.
Try to breathe into your chest and back rather than belly. Tense your upper ab muscles in different ways in the mirror until you see which muscles pull your ribs in. Try to tense these muscles as your breathe and throughout the day.
Don't do exercise that flares your ribs, ensure any movement you do keeps your ribs and stomach aligned. Sometimes means slight incline or decline depending on lift. You may be bracing incorrectly if doing heavy lifts, again make sure to take breath into chest and back, not just stomach. Brace the same an muscles as you found above.
>had a massive issue with stomach pain and inflammation due to flared ribs and belly breathing/ bad bracing.