Thank you for confessing it's not all fun.

I decided to loosen the shoulderstraps and that seemed to help, but I also think I need to stop slouching. Although when I went grocery-shopping yesterday, my back started to ache from (un)consciously tightening my muscles. I hope to be able to relax a little in the future. So far I'm simply too aware of the bra's presence.
But my breasts appear to appreciate the support, so I'm not giving up yet.