Hidden pain in the left side of the lower abdomen may be intestinal inflammation or tumors, endometritis, ectopic pregnancy, varicocele, etc. 1. Intestinal inflammation or tumor: ulcerative colitis, intestinal tumors can cause hidden pain in the left lower abdomen. 2. Endometritis: this disease is mainly due to a variety of microorganisms mixed infection of the endometrium, usually in sexually active reproductive women, the patient will appear in the left side of the lower abdomen hidden pain, accompanied by increased vaginal discharge, fever and other symptoms. 3. Ectopic pregnancy: due to factors such as reproductive system diseases or injuries, the fertilized egg is deposited outside the uterine cavity, resulting in hidden pain under the left side of the abdomen, accompanied by menopause, and severe patients will experience shock, fainting and other symptoms. 4. Varicocele: This disease is mainly related to the congenital developmental abnormality of the spermatic vein, the involvement of acquired diseases, heredity and other factors, resulting in the patient’s spermatic vein reflux obstacle, thus abnormal expansion, the patient will appear in the left side of the abdomen under the hidden pain. In addition, left-sided adnexitis can also cause left-sided abdominal pain. It is recommended that the patient go to the hospital in time, and under the diagnosis of the doctor, according to the patient’s condition, take targeted treatment.