Can't believe I'm answering this question...
No, my boobs were not/are not tender at all. You could punch me in the chest and all I would feel is the bounce. Although, my friends (the ones that are girls, obviously) randomly will say that their boobs hurt upon impact. I guess it's different for everyone, and I seem to be a bit unusual, even if you ignored the fact that I'm trans. For example, I recently found out I have a really low waist

. My mom said something about my pants always being too low, and I was like "What do you mean? I wear my pants at my waist." Anyway, getting off topic.
The point is, everyone's different, so it would probably be different for you than it is for me or anyone else.