Growing Pains: This is the most common cause of leg pain in children around this age. Growing pains are characterized by recurrent, bilateral leg pain, typically in the calf or thigh, which occurs in the late afternoon or evening and resolves by morning. The pain is usually mild to moderate and can be relieved with stretching or massage.

Muscle Strain: Overuse or injury from sports or physical activities can lead to muscle strain, causing leg pain.
Shin Splints: Medial tibial stress syndrome, commonly known as shin splints, is a condition that causes pain in the front or sides of the lower legs due to overuse or repetitive stress on the muscles and bones.
Osgood-Schlatter Disease: This condition affects the knee, causing pain and swelling below the kneecap, typically in adolescents during growth spurts. It's related to overuse of the knee joint.

Osteosarcoma or Other Bone Cancers: Although rare, bone cancers can present with persistent, unexplained pain in the legs. Early detection is crucial for effective treatment.
Septic Arthritis or Osteomyelitis: Infections within the joint or bone can cause severe pain, redness, and swelling. Prompt diagnosis and treatment are essential to prevent long-term damage.
Slipped Capital Femoral Epiphysis (SCFE): A condition where the ball at the upper end of the femur (thigh bone) slips out of place, causing hip pain that can radiate to the leg. It requires urgent medical attention to avoid complications.

Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. It can lead to joint hypermobility and pain.
Legg-Calve-Perthes Disease: A condition where the blood supply to the ball at the top of the femur is disrupted, leading to the bone's death and collapse. It typically affects children between the ages of 4 and 10.
Juvenile Idiopathic Arthritis (JIA): A chronic autoimmune disease that causes joint inflammation and pain. While it primarily affects the hands and feet, it can also involve the knees and other joints, leading to leg pain.