There is a long hard lump on the left side of the abdomen after lying down, which may be physiological intestinal feces, pathological intestinal tumor, female gynecological ovarian tumor and other phenomena. It needs defecation, tumor, cyst symptomatic treatment and so on. 1. Physiological feces: the left side of the abdomen has the left section of transverse colon, descending colon, sigmoid colon. Patients with constipation, feces are easy to stagnate in the left side of the colon intestinal tract. At this time, lying down, you may feel a hard lump on the left side of the abdomen, which is caused by dry feces blocking the intestinal tract. 2. Intestinal tumor: such as small intestine tumor, colorectal cancer, etc. It can manifest as abdominal pain, intestinal obstruction. It may manifest as abdominal pain, intestinal obstruction, intra-abdominal mass, etc. When palpation is performed, the left side of the abdomen may be found. On palpation, a long hard lump may be found in the left abdomen. 3. Female ovarian tumor: including benign and malignant tumors. Abdominal distension may appear when the tumor increases in size, and lumps may be found in the abdomen. Once found, surgery and other treatments should be carried out immediately. If there is a lump in the abdomen lying down, you need to consult a doctor as soon as possible, complete the examination, and follow the doctor’s instructions to treat it accordingly after the diagnosis is clear.