My hair is definitely damaged right now from all the colorings, and I straighten about twice a month, if that. However I can remember that even when I was younger, my hair still didn't really swing. It may have been due to the fact that it's so thick, or maybe it's because my hair is so protein sensitive? No idea.
Fmas - I haven't heard of an herbal rinse, but I should look into it! I wouldn't even know where to start though..