How to know if i have testicular cancer/torsion?

Pain &/or hardness: Testicul cancer is a hard, usually painless, non-tender lump on or in testicle, occasionally painful if there is a bleed within the tumor. Surrounding, non-tender hydrocele can be present. Torsion results in acute onset of severe scrotal pain with marked tenderness. Testis can be high in scrotum & also develop a rapid onset, tender hydrocele. Ultrasound will demonstrate absence of testicular blood