Hard lumps below the epididymis where the testicles are attached are mainly considered to be related to inflammation, cysts, tumors, syringomyelia and other causes. 1. Inflammation: such as chronic epididymitis, which can lead to the appearance of a swelling in the epididymis, and then the symptoms of a hard lump. 2. Cysts: the presence of cysts in the epididymis and testicular region can also lead to this symptom. 3. Tumors: Tumors in the epididymis and testicles are also common causes of this symptom. 4. Syringomyelia: It can lead to the appearance of a lump on one side of the scrotum and is characterized by chronic, painless growth. 5. Other diseases: such as varicocele, epididymal tuberculosis, testicular torsion and other diseases may also cause this symptom. The causes of this symptom are complex and varied. We must pay attention to it and go to regular hospitals for medical treatment.