Is this in any way related to pregnancy? Its constant pain... feels like something is tearing and when trying to have a feel to work out where the pain directly is... it all feels bruised... i have had the first show of my boobs lactating this morning with a dribble from each. First pregnancy so id rather ask and see if anyone can relate?                 
                             
        
Re: Stabbing/tearing pain beneath the boob
You should always ask your doc. The only thing that helps the pain for me is going in the pool. She will slip out for a while but she always makes her way back in.
Same here....I have had nerve stretches and pinches before as result of some yoga poses so I am familiar with the feeling. It is especially bad when I lay on my sides...which is ironically the only way I can lay these days