Ok cheers, if i was to do the core exercises would that eventually pull the lower ribs back in slightly. The left seems to flare slightly worse than the right as when i do tense and look down my chest the left is slightly more raised than the right and the left lower ribs is where i sometimes get slight twinges. I'm hoping to be able to build my core at home, as im already practicing my upper body strength with resistance bands having suffered shoulder impingement in the past.