Similar problem
Years ago, I was doing weighted dips- I loved them- and worked up to 100 pounds attached to a judo belt for sets of around 6 reps. I went all the way down and, while doing so one day, felt in the center of my chest a sharp pain.
For over 1 year couldn't do any heavy chest work, nor even light benching.
For 3 years afterwards I could not bench without discomfort.
I have often read on this board praise for weighted dips. Not knocking them, but this is the third time I have read on a bbding board about a weighted-dips related injury. I wouldn't advise doing weighted dips and going all the way down. Dips are great at the end of a chest workout and work the tris- there are other safer movements to build up the chest than weighted dips.
Just my .02