I felt the bone just under my boobs the other week as well and actually felt sick, just really freaked me out lol.
I have also noticed when sitting in my car I am shorter, weird I have lost quite a lot of padding obviously and thought that my seat had sunk he he he.
I love these funny little changes and just wonder what on earth I am gonna find next, hope its not gross like the breast bone thingy though ewwww still cringe.