Your weight (96 kg with PCOS and hypothyroidism) is the main driver here - heavy pendulous breasts plus shoulder and bra-strap pain is what we call macromastia with postural strain. Sagging at 37 won't reverse with creams or exercises. Two things: get your
thyroid profile rechecked while on Thyronorm 50, and start real weight reduction - even 8-10 kg lifts the shoulder pain a lot. Meanwhile use a rigid wide-strap sports bra, not a regular one. If pain persists or you get skin rash under the fold, a reduction mammoplasty opinion from a plastic surgeon is reasonable. Message me on Practo with your latest
TSH report and I'll plan the medical side properly.