Left lower rib tenderness may be an adverse symptom caused by intercostal neuritis, and also occurs when suffering from costochondritis, pleurisy and other diseases, it is recommended to consult the doctor in time for relevant examinations. 1. Intercostal neuritis: Suffering from intercostal neuritis may cause tenderness in the left lower rib cage, usually accompanied by pain, burning sensation and other symptoms, discomfort may also occur around the affected area, the discomfort will be aggravated after strenuous exercise or overexertion, and tightness around the chest may occur in some patients. 2. Costal chondritis: Costal chondritis may also lead to soreness and tenderness of the left lower rib cage, patients will experience different degrees of pain, swelling of the affected area, discomfort will be more pronounced when pressed, and may lead to pins and needles around the left lower rib cage, soreness and swelling, and other symptoms, and some patients will be aggravated by exposure to cold. 3. Pleurisy: left lower rib soreness may also be suffering from discomfort caused by pleurisy, suffering from this kind of disease around the chest will appear obvious pain, violent cough or deep breathing will make the symptoms more intense, the discomfort will be radiated to the whole thorax, serious will cause breathing difficulties. Such discomfort requires prompt medical attention, and under the guidance and advice of a doctor, appropriate treatment should be chosen to avoid aggravation of the condition.