A hard lump in the groin that hurts when pressed may be caused by enlarged inguinal lymph nodes, inguinal hernia, sebaceous cysts and so on. 1. Enlarged inguinal lymph nodes: when inflammation occurs near the inguinal lymph nodes, the inflammatory stimulus will lead to local edema, and local lymph node enlargement will occur, usually with mild pain and pressure pain. 2. Inguinal hernia: probably due to prolonged engagement in high-intensity physical labor, the original local defect in the inguinal area will gradually expand, eventually leading to tissue protrusion of the inguinal area to the surface of the body, which will be painful when pressed hard. 3. Sebaceous cysts: Sebaceous cysts can be caused by trauma, inflammatory infections, and metabolic disorders. It can also be caused by the blockage of sebaceous gland ducts, which will also hurt when pressed. If there is a hard lump in the groin that hurts when pressed, and continues to be unrelieved, you need to seek medical treatment.