I have pain under my right rib since late 2nd tri - the doc said it's probably the baby kicking, or the muscles getting pulled/expanded which is normal for pregnancy. There's a small risk that there's something wrong with the liver but he won't be able to tell without running diagnostic tests. I opted not to as I don't intend to do any surgery/treatment while pregnant and will follow up if the pain persists after delivery. I'm pretty sure it's just normal pregnancy pain though, I read online it's quite a common symptom.
I'm experiencing the same thing too. it's very painful sometimes. as soon as I do physical activities, the pain starts to kick in. then I will just sit and rest. it does go away but will come back once I'm active again. its really stressing me out too.