As far as I know a bra might make it worse. I mean, if it's sensitive to pressure, why compress it all the time with a bra? It might provide some protection against contact, but... Just avoid putting pressure on them as much as possible, and do your best not to sleep on your belly. Oh, and uhm, if you feel that even your shirt is being a problem, like it was for me for a while soon after I started HRT and it was super tingly, it may feel really weird or wrong, but it might bring you great relief to just remove it for a while, if you're alone. And if it gets tingly, don't be shy on putting tons of moisturizer in the area.
But honestly, I don't think there's much to do.