I went bra shopping this weekend- first time in about 5 years. I usually wear a bra top instead. I went to M&S first. The assistant decided I was a 38D. She brought me a selection of bras to try on. They all looked fucking awful and felt worse. I left without buying anything and went to Bravissimo. The assistant there was brilliant. I tried on over a dozen bras in different sizes and styles before opting for this one in a 32FF. 
It definitely fits. The band is snug but not too tight. The gore is flat on my chest. The straps don't dig in. My breasts fill the cups nicely with no overspill.
BUT after wearing it all day, I've found it very uncomfortable-particularly in the band. I've just taken it off and there are red marks along my back and where the gore sits.
Does it just need to 'bed in' a bit? Am I just unused to wearing a bra? I'm a bit disappointed because it cost a lot and it looks like a good fit.
Help!