To the person who just tripped in here googling for underwired bras make me sore, then I should tell you this. If your bra makes you sore, it is the wrong size. Probably too tight. And possibly in the wrong places. If you are in the UK, go somewhere like a department store's lingerie department and get properly fitted for a bra. You don't even have to buy it, just try it on and "think about it." Or buy your underwear in M&S, where you can try it on.
An underwired bra should fit tightly round the back, and the wires in the middle should sit against your rib cage, so you are actually supported. Most people are wearing a bra size or three too big - the measurement is really around your rib cage, underneath your breasts, so you're much more like to be a 32DD rather than a 36DD or whatever. And anyway, all makes are different so you really do have to try them on.
Here endeth the underwear lesson.