I don't think you can dislocate a rib (ribs dont have a socet to dislocate from) if it hurts to breath in and laugh or cough then it's most likely severely bruised or fractured. It can and does happen quite often in the last trimester. Get checked by your Dr to make sure no problems arise from it. Mostly you will prob be told to take it easy and ride it out...
Never had a dislocated or broken rib from pregnancy but with my first he did fracture it pretty darn bad so i kno how you feel a lil bit i hope you get better soon hunn
My sisters rib got broken bcuz of pregnancy. They wrapped her ribs aftrr she gave birth