Some hospitals give you a bra to wear after surgery and some wake up wearing it. I got one about three days after surgery. You might want to ask about it when you go to the hospital for your pre-op stuff.
I was given a bra after surgery from the hospital, it was super comfy but not much support, my surgeon said about a sports bra, but then my scar popped open at the top and my nurse said that sports bra was probably the WORST type of bra to have after OHS!
Good luck to you xxx