Rib Pain

Anyone else getting pain in their rib cage? I'm at 27 weeks and my bump is still relatively small, but I feel like it's putting a lot of pressure on my lower rib cage, especially when I have to sit all day for work. Anyone else getting this? Any stretches or anything to recommend for it? I do a half hour prenatal yoga routine every morning which does wonders for my back, but lying down seems to be the only thing that makes my ribs feel better.