The penis is hard and painful, considering the penile sclerosis, penile trauma, penile abnormal erection and other causes. 1. penile sclerosis: refers to the penis spongy interval of chronic fibrous tissue hyperplasia caused by hard knots, plaques as the characteristics of the disease, its etiology is not yet completely clear, the main considerations and trauma, genetics and other factors. Sclerodactyly can lead to erection pain, penile hardness and other uncomfortable symptoms. 2. Penile trauma: when the penis is subjected to external collision or impact, it can lead to localized pain and swelling, resulting in hardening and pain. 3. Abnormal penile erection: it refers to the continuous erection of the penis caused by non-stimulation conditions, or does not weaken even after orgasm, and this state lasts more than 4 hours, often accompanied by pain. There may be other reasons why the penis is hard and painful, so it is recommended to actively seek medical advice and treatment under the guidance of a professional physician.