Muscle strain: This is often the most common cause of inner thigh pain, resulting from overstretching or tearing of the muscles in the thigh, particularly the adductor muscles. Activities that involve sudden stops, changes of direction, or direct blows to the thigh can lead to muscle strain.

Groin pull or adductor strain: Similar to muscle strain, but specifically involves the adductor muscles of the thigh. It's common in athletes who participate in sports that require quick changes of direction.
Thigh contusion: A bruise of the thigh muscles, usually caused by a direct blow to the thigh, which can cause pain and swelling.
Osteitis pubis: An inflammatory condition affecting the pubic bone and the surrounding muscles, often seen in athletes. It can cause pain in the groin area that may radiate to the inner thigh.
Referred pain from the hip: Conditions affecting the hip joint, such as osteoarthritis or a labral tear, can refer pain to the inner thigh.

Deep vein thrombosis (DVT): Although less common, DVT is a potentially life-threatening condition that requires immediate medical attention. It can cause pain, swelling, and warmth in the affected leg.
Femoral hernia: A hernia in the groin area that can cause severe pain, especially if it becomes incarcerated or strangulated.
Osteonecrosis of the femoral head: A condition where the blood supply to the head of the femur is disrupted, leading to bone death. It can cause hip pain that may radiate to the thigh.
Inguinal lymphadenopathy: Enlarged lymph nodes in the groin area can be a sign of infection or malignancy and may cause pain in the inner thigh.

Meralgia paresthetica: A condition characterized by numbness, tingling, and burning pain in the outer part of the thigh, but can sometimes affect the inner thigh due to compression of the lateral femoral cutaneous nerve.
Piriformis syndrome: Although more commonly associated with pain in the buttock and back of the leg, in rare cases, it can cause referred pain to the inner thigh due to compression of the sciatic nerve.
Neoplastic processes: Tumors, either benign or malignant, affecting the bone, muscle, or soft tissues of the thigh can cause pain, although they are rare causes of inner thigh pain.
Infections: Such as abscesses or cellulitis in the thigh, which can cause pain, swelling, and redness.