A hard lump on the chest may be caused by congenital factors, costochondritis, folliculitis, keloid, sebaceous cysts and other factors. 1. Congenital factors: a hard lump on the chest may be a bony bump, which is caused by the excessive development of the sternum in the congenital development, and if it does not affect the normal life, it can be temporarily observed and not dealt with. 2. costochondritis: the cause is not completely clear, mostly in the upper chest, pain recurrence, sometimes heavy, sometimes light, serious cases may appear abscess, manifested as rib cartilage expansion, the formation of pseudo-hard lumps, with pressure pain. 3. Folliculitis: Malassezia folliculitis occurs in the chest, back, etc., manifested as scattered distribution of hemispherical red papules or pustules, the surface is glossy, surrounded by a red halo, and some patients have itching symptoms. 4. Keloid: keloid patients in the chest skin trauma, may gradually appear keloid hyperplasia, manifested as nodular or striated hard lumps, the surface is smooth and hard, accompanied by the expansion of capillaries, there may be varying degrees of itching. 5. Sebaceous cysts: mostly due to sebaceous gland duct obstruction, gland contents accumulation and lead to cysts, commonly in young adults, manifested as a normal skin color of the round swelling, smooth surface, most of the single hair, the center of the black depression can be seen in the size of the tip of a needle, pressure can be white content overflow. A hard lump on the chest may also be due to other factors, it is recommended that the patient seek medical attention in a timely manner, under the guidance of the doctor for relevant examinations, in order to clarify the cause of the symptomatic treatment.