Epididymitis: This condition, which is an inflammation of the epididymis (a tube at the back of the testicle that stores and carries sperm), can cause yellow, jelly-like semen due to the presence of pus and dead sperm. The inflammation can also lead to pain in the pelvis and groin area, making it a likely explanation for the symptoms described.

Prostatitis: Inflammation of the prostate gland can lead to changes in semen appearance, including a yellowish color, and can cause pain in the pelvic and groin areas.
Urethritis: Infection or inflammation of the urethra can cause changes in urine and semen, including color and consistency, and may lead to pelvic and groin pain.
Orchitis: Inflammation of one or both testicles, usually caused by bacterial or viral infections, can lead to pain and changes in semen.

Testicular Torsion: Although less likely, this is a medical emergency where the spermatic cord becomes twisted, cutting off the blood supply to the testicle. It causes severe pain and can lead to changes in semen if the condition affects sperm production or leads to infection. Prompt diagnosis is crucial to save the testicle.
Testicular Cancer: While rare, testicular cancer can cause changes in testicular size, consistency, and potentially affect semen. It's essential to rule out this condition due to its serious implications.

Semen Allergy (Human Seminal Plasma Hypersensitivity): A rare condition where the body reacts to semen, potentially causing inflammation and changes in semen appearance.
Genital Tuberculosis: A rare condition in many parts of the world, genital TB can affect the genital tract, including the epididymis, prostate, and testes, leading to a variety of symptoms including changes in semen and pelvic pain.