Osteitis Pubis: This condition is characterized by inflammation of the pubic bone and surrounding structures, often presenting with groin pain that worsens with activities such as twisting, turning, and hip extension. The presence of point tenderness at the pubis and normal X-ray findings support this diagnosis, as osteitis pubis may not always show abnormalities on initial X-rays.

Femoroacetabular Impingement (FAI): FAI can cause hip pain, especially with activities that involve twisting or turning, due to abnormal contact between the femoral head and acetabulum. While it might not directly explain lower abdominal pain, referred pain patterns could contribute to the presentation.
Sports Hernia (Athletic Pubalgia): This condition involves a weakening of the abdominal wall, particularly in the inguinal region, without a palpable hernia. It can cause chronic groin pain that worsens with activity, especially those involving twisting or sudden changes in direction.
Stress Fracture: Although the X-ray is normal, stress fractures, particularly of the femoral neck or pubic rami, might not be visible on initial X-rays. They can cause pain in the groin, hip, and lower abdomen, especially with weight-bearing activities.

Testicular Torsion: Although less likely given the chronic nature of the pain, testicular torsion is a medical emergency that can present with acute onset of severe groin pain and should always be considered, even in the absence of typical scrotal symptoms.
Appendicitis: While the pain pattern is atypical for appendicitis, it's crucial to consider this diagnosis due to its potential severity. Appendicitis can sometimes present with pain in the lower abdomen or groin, especially if the appendix is retrocecal.
Ovarian Torsion: In female patients, ovarian torsion is another emergency that can cause severe, acute pain, often in the lower abdomen or groin.

Avulsion Fracture: An avulsion fracture of the lesser trochanter or other pelvic structures could cause pain in the described areas, especially if associated with a significant injury or repetitive stress.
Inflammatory Spondyloarthropathy: Conditions like ankylosing spondylitis can cause chronic hip and lower back pain, and while less common in this age group without other symptoms, they should be considered in the differential diagnosis of chronic pain.
Psoas Abscess: A psoas abscess can cause hip and lower abdominal pain due to the involvement of the psoas muscle, but it is relatively rare and usually associated with other systemic symptoms of infection.