@up4challenge
First, you probably need to be measured and fitted properly. I started off a 50DD and I wear a 34F/G (depending on brand) now. All the sizes in between have not been uniform. At first I was not not losing evenly. Now I am just pretty much only losing band size and my cup is the same. Are you sure you are a 40 band? What are your above and below the band measurements? At your height and weight you might be a 38 or a 36 and instead of a DD need DDD. I am just guessing...
I really like Soma bras, specifically Stunning Support, they can fit you and work with you and they have some with great lift and back smoothing.
https://www.soma.com/store/category/stunning-support/cat8589275?CAWELAID=120218660001718742&CAPCID=92514671312&cadevice=c&agid=24207423872&catci=aud-297954731427:kwd-179058265472&gclid=Cj0KCQjwwevLBRCGARIsAKnAJvfEKf7eKOsPLgYHLMTRYcLQQBe8IJLi9p9UdNlLURrIfjBN8E9gLlEaAq9OEALw_wcB
If you do not live in an area where you can go some place and be fitted then try using the guide here...
https://www.reddit.com/r/ABraThatFits/wiki/beginners_guide
Do all the measurements to the best of your ability and use the calculator to see where you are.
As far as the pain, that incision I had near the bra line healed very well, I can't even see it now. I was able to wear bra comfortably after 2 weeks. I kept it covered with gauze until that time so it had cushion. Have you asked your Dr about it? Also a bra that fits better might solve the issue.
Good luck