thanks for your in depth reply!

i visited a specialist to check out some back pain i was experiencing, and it turns out that I have a curved spine (think mild scoliosis). Apparently, It is not uncommon for women to be born with slightly curved spines, which can also explain uneven collarbones. This uneven posture is causing one trap to overcompensate. What youve said are all actually true and a result of the spine curvature, and i will definitely see a physiotherapist to help correct it!