I have been getting the same pain... sorry to say it only gets worse I find taking a little walk or resting with my right arm up (ie. on the back of the couch) helps a little. At first I would always take my bra off, thinking it was the pressure from the bra, but like Cyathea said that only makes it worse! Also, avoiding big meals helps. When I am really full it is always more uncomfortable.

I asked my Ob and he said that your liver is on the right side and therefore there is less room. My bub is head down and he said it's his bum pushing up against it!