Bone pain under the chest of a pregnant woman is a condition that refers to a lesion in the rib cage or rib cartilage. There are three main reasons for this: firstly, there is a fracture or crack in the rib cage, which leads to localized edema and bruising, gradually forming inflammatory edema and swelling, which can cause significant stimulation of the peripheral nerves, leading to increased pain; and when coughing or panting, the thoracic heave can also cause further stimulation of the rib fracture, leading to further pain. further aggravation of the pain. The second condition is due to costochondritis, which is mainly caused by cold or frequent trauma and collision, resulting in the formation of local foci of sterile inflammation and the stimulation of peripheral nerves by inflammatory metabolites, leading to pain. The third condition is the intercostal muscles, which are mainly the muscles between the ribs and the rib cage called intercostal muscles. If there is a strain, strain or external collision of these muscles, there will also be some inflammatory edema and swelling of bruising, which will stimulate the surrounding peripheral nerves and also cause significant pain; however, when pressing with the hand, it feels like pain at the location of the rib cage, which is actually the intercostal muscle.