Left side pain under the rib cage hurts more when you inhale may be related to cardiac neurosis, pleurisy, intercostal neuralgia, and so on. 1. Cardiac neurosis: If there is long-term anxiety and tension, the central nervous system may function abnormally, and the cardiovascular system, which is regulated by the plant nerves, may be disturbed, resulting in symptoms such as pain when breathing and pain in the precordial area. 2. Pleurisy: If the pleura is stimulated by virus or bacteria, it will easily lead to pleurisy, which is mainly manifested as chest pain, cough, chest tightness, etc., and even pain when breathing may also occur. 3. Intercostal neuralgia: if multiple peripheral neuritis, etc., it is easy to cause irritation to the intercostal nerves, resulting in intercostal neuralgia, which may cause more pain when inhaling. As you can see, if the left side of the rib cage hurts more when you breathe in, you should also pay attention to whether there are other accompanying symptoms, etc. If there is no relief, it is recommended that you consult a doctor to find out the cause of the problem and then treat it under the guidance of the doctor.