Hummmm Definitely sounds like there is a market for Kevlar lined bras. 

In fact it would be funny if it wasn't so serious.

Beware and take care

Huggs

Catherine

Taking warm showers always helped me when I'd hurt my breasts and/or nipples.

One thing I did after I had my piercings was to bandage my nipples with a little tape and gauze, it seriously helped to keep me from hurting them when they touched anything.  That may not be a long term solution, but it might help for when you accidentally whack one.