A hard lump below the rib cage may be a lipoma, or it may be caused by costochondritis or subcutaneous injury. 1. Lipoma: it is a slow-growing fat mass, commonly found between the skin and the lower layer of muscle. It is a non-cancerous mass formed by the overgrowth of fat cells, and it can grow anywhere in the body. Most of the lipomas will not show other symptoms, but will be manifested as a hard lump underneath the ribcage. 2. Costochondritis: the cause is related to labor injury and trauma, acute onset of the disease may feel tingling in the chest, and chronic onset of the disease may appear swelling and bulging of the costochondral bone, and press the outer edge of the sternum will feel obvious pain, which may be manifested as a hard lump below the rib cage. 3. Subcutaneous injury: If there is a hard lump under the rib cage, it may also be the osteophytes of the rib cage, may also be caused by rib fractures, subcutaneous tissue damage to the blood vessels rupture, the gradual formation of subcutaneous hematoma, when pressed with the hand will be manifested as obvious pain. A hard lump under the rib cage may also be due to other reasons, it is recommended to consult a doctor in time, complete the relevant examination, and carry out relevant treatment under the guidance of a professional doctor.