Muscle strain or pull: This is a common injury in young adults, especially those who are physically active. The groin area is prone to strains due to the convergence of multiple muscle groups, including the adductors, flexors, and abdominal muscles. A sudden or forceful movement can lead to a strain, resulting in severe pain.

Inguinal hernia: Although more common in older adults, inguinal hernias can occur in younger individuals, especially those with a family history or who engage in heavy lifting or straining activities. The hernia can cause severe groin pain, especially if it becomes incarcerated or strangulated.
Epididymitis or orchitis: Inflammation of the epididymis or testis can cause severe groin pain, often accompanied by swelling, redness, and warmth of the affected testicle. These conditions are usually caused by bacterial or viral infections.
Groin abscess: A collection of pus in the groin area can cause severe pain, swelling, and redness. Abscesses can arise from infected hair follicles, sebaceous glands, or as a complication of another condition like hidradenitis suppurativa.

Testicular torsion: This is a medical emergency that requires prompt attention. Torsion of the testicle can cause severe, sudden groin pain, often accompanied by nausea, vomiting, and abdominal pain. If not treated promptly, it can lead to loss of the testicle.
Appendicitis: Although the appendix is located in the lower right abdomen, the pain can sometimes radiate to the groin area, especially if the appendix is retrocecal (located behind the cecum). Appendicitis is a surgical emergency.
Psoas abscess: An abscess of the psoas muscle can cause severe groin pain, often accompanied by back pain, fever, and limited hip movement. This condition can be life-threatening if not treated promptly.

Osteitis pubis: Inflammation of the pubic bone and surrounding structures can cause chronic groin pain, often seen in athletes who participate in sports that involve kicking or rapid changes of direction.
Avulsion fracture: A fracture of the bone where a muscle or tendon attaches can cause severe groin pain, especially if the fracture occurs in the pubic bone or ischium.
Nerve entrapment: Entrapment of the ilioinguinal, iliohypogastric, or genitofemoral nerves can cause severe groin pain, often accompanied by numbness, tingling, or burning sensations in the groin or thigh.