Epididymitis: This is often the most common cause of scrotal pain, especially in sexually active young men. It is an inflammation of the epididymis, usually caused by bacterial infection.

Orchitis: Inflammation of one or both testicles, usually caused by viral or bacterial infections. It can occur alone or in conjunction with epididymitis.
Testicular torsion: A condition where the spermatic cord becomes twisted, cutting off the blood supply to the testicle. It is a medical emergency but less common than epididymitis.
Hydrocele: An accumulation of fluid in the tunica vaginalis, a potential space around the testicle. It can cause scrotal swelling and discomfort.
Varicocele: An enlargement of the veins within the scrotum, similar to varicose veins. It can cause aching or discomfort, especially after long periods of standing.

Testicular torsion: Although listed under other likely diagnoses due to its potential for scrotal pain, it's crucial to emphasize as a "do not miss" due to its emergency nature and the need for immediate surgical intervention to save the affected testicle.
Testicular cancer: While less common, testicular cancer can present with scrotal pain or a painless testicular mass. Early detection is key for effective treatment.
Fournier's gangrene: A rare but life-threatening condition characterized by necrotizing fasciitis of the genitalia. It requires immediate medical attention.

Spermatocele: A cystic structure filled with sperm, usually attached to the epididymis. It can cause discomfort but is typically painless.
Scrotal cellulitis: An infection of the skin and subcutaneous tissue of the scrotum, which can cause pain, redness, and swelling.
Henoch-Schönlein purpura (HSP): A form of vasculitis that can affect various parts of the body, including the scrotum, leading to pain and swelling.
Scrotal abscess: A collection of pus in the scrotum, usually as a result of a bacterial infection. It can cause severe pain and swelling.