Hard lumps in groin muscles may be caused by inguinal hernia, fibroma, inflammation and infection. 1. Inguinal hernia: after suffering from this disease, there is usually no abnormal symptom when lying down, but there is obvious lump in the groin when standing or walking, and when there is incarceration, the intestinal tube is bruised, and the texture is hard when palpated. 2. Fibroma: under the influence of genetic and lifestyle factors, it may cause fibroma disease. When it occurs in the groin area, with the increasing volume of the lump, it will cause pressure on the skin, which will lead to hard lumps in the groin on palpation. 3. Inflammation and infection: Inflammation can be caused when the groin muscle is infected by bacteria, and the inflammation will cause stimulation to the muscle, causing inflammatory edema, redness, swelling, heat and pain in the area, and hard lumps can appear on palpation. Hard lumps in groin muscles may also be caused by other reasons, such as hemangioma, myofibroma, lymphatic metastasis of malignant tumors, etc. It is recommended that patients go to the hospital in time.