Growing pains or overuse injury: This is a common condition in adolescents, especially during growth spurts, where the bones, muscles, and tendons are subjected to increased stress, leading to pain.

Stress fracture: Common in adolescents, especially those involved in sports or activities that involve repetitive stress on the bones.
Osgood-Schlatter disease: A condition that affects the upper tibia, causing pain and swelling, often seen in adolescents during growth spurts.
Slipped capital femoral epiphysis (SCFE): A condition where the ball at the upper end of the femur slips out of place, more common in obese adolescents or those with hormonal imbalances.

Bone cancer (e.g., osteosarcoma, Ewing's sarcoma): Although rare, these conditions can be deadly if not diagnosed and treated promptly. Persistent, worsening, or nighttime pain should raise suspicion.
Infection (e.g., osteomyelitis): Bacterial infections of the bone can cause severe pain and have serious consequences if not treated promptly.
Trauma: Fractures or other traumatic injuries can cause significant pain and must be ruled out, especially if there's a history of injury.

Fibrous dysplasia: A condition where normal bone is replaced with fibrous tissue, leading to weakened bones and potential for fractures.
Gaucher's disease: A genetic disorder that can cause bone pain due to the accumulation of fatty substances in the bones.
Hypertrophic osteoarthropathy: A rare condition characterized by excessive bone growth, leading to pain and swelling in the affected areas.