Hidden pain near the navel does not exclude the possibility that it may be caused by smooth muscle sarcoma, but in addition to smooth muscle sarcoma, it may also be caused by appendicitis, gastroenteritis and other diseases. 1. Smooth muscle sarcoma: smooth muscle sarcoma is a malignant tumor originating from smooth muscle, which occurs in the abdominal cavity and can be manifested as a lump near the navel, thus producing a vague pain. It is recommended to go to the hospital for X-ray barium meal, ultrasound gastroscopy and other related examinations to clarify the cause of the disease. 2. Appendicitis: Inflammation of the appendix caused by blockage of the appendix lumen or secondary bacterial infection. Appendicitis in the early stage of the disease may appear in the belly button near the symptoms of hidden pain, with the development of pain intensified, and gradually shifted fixed in the right lower abdomen in the part of the Mai’s point. 3. Gastroenteritis: mostly due to pathogenic microorganisms, food allergies, autoimmune diseases and other causes of gastrointestinal inflammation, can be manifested as vague pain near the navel, accompanied by diarrhea, nausea, vomiting and other symptoms. If there are frequent hidden pains near the navel may also be other causes, it is recommended to go to the hospital for examination, to clarify the cause of the disease under the guidance of the doctor to standardize the treatment.