The cause of left lower rib pain may be costochondritis, intercostal neuralgia or muscle strain, etc., most of the pain can be relieved by hot compresses, and should be actively treated. 1. Costal chondritis: costal chondritis is mainly due to various reasons, such as trauma, strain, inflammation, tumor and infection, leading to the junction of the costal cartilage and the sternum need to have an inflammatory reaction, resulting in obvious pain and swelling symptoms of the chest wall, through the hot compresses can to a certain extent alleviate the pain, which can be manifested as the pain in the left lower ribs, a hot compress will be fine. 2. Intercostal neuralgia: it is caused by various reasons such as viral infection, trauma, thoracic spine disease, tumor and so on, leading to the damage or stimulation of thoracic nerve roots or intercostal nerves, thus triggering the pain in the corresponding intercostal innervation area, which can be manifested as tingling, radiating pain, and physiotherapy such as hot compresses can also relieve the pain to a certain extent. 3. Muscle strain: If you have a strenuous exercise, or lifting heavy objects, can cause muscle strain in the ribs, thus causing pain, can be localized hot compresses to ease the discomfort, and can be gradually relieved after rest. If the pain continues to be unrelieved, it is recommended to go to the hospital for timely examination and treatment.