I've had the same pain that you are describing - for me it wasn't the boob thing, it was a problem with my intercostal muscles (between the ribs) pulling too tight and all my ribs were compressing and I was not breathing properly!

My suggestion is to get a massage first off - that's what I did and the therapist was able to indicate an area of tightness that didn't feel right and she recommended I go see an osteo. That'd be my advice!