I know exactly what you're talking about.
One of my Pekes (Dino) had the same thing. It never bothered him but whenever I lifted him up by the chest, I could sometimes feel it sticking into my hand.
I think it's a weird genetic thing that some critters get. Not harmful that I know of.
Unless it's a hernia, but that wouldn't feel sharp and bony, I wouldn't think.
At first I thought it was a hernia... but it's not... it's bony.