There are three main reasons for pain in the lower left side of the rib cage: First, because there are external obliques, internal obliques and transverse abdominis muscles in the lower left side of the rib cage, these muscle tissues may produce more inflammatory metabolites locally when they are subjected to external collision, injury, local overwork, strain or frequent cold. These metabolites will stimulate the peripheral nerves, so painful symptoms will appear, especially when cold and strain will lead to more obvious symptoms. Second, there may be abnormalities in the deep organs under the left rib cage, such as the stomach, spleen, and pancreas. If there is an enlarged spleen, pancreatitis or other diseases in the stomach, it may cause pain in this area. After this situation, you can go to the hospital for a local ultrasound examination to see if there are any abnormalities in the deep organs, and then carry out targeted treatment. If there is no abnormality, you can apply heat to the area or apply magnetic therapy patch to effectively relieve the symptoms of the muscle.