Do not worry so much. Hormonal changes as increase in the progesterone during pregnancy can lead to rib pain. Also it may be due to your growing breasts also. Caution that you cannot take any anti-inflammatory medicine. If your pain becomes unbearable, you can consult your gynecologist. Here are some advice to relieve your rib pain: Wear loose clothes and a bra of a correct size that provides support to your enlarged breast, thereby reducing the rib pain. Get yourself engaged in regular pregnancy exercises, breathing exercises and yoga. Sit and sleep in the right position. Use a small pillow to support your back.Sleeping on the side of the pain also helps in decreasing the rib pain. Take regular short walks and do not sit or stand in the same position for a long time. Get some gentle massage over the area of pain. This will relax the muscles and reduce the pain. All the best. Take care.