Otjher possibilities are Dehydration or low amounts of potassium, sodium, calcium, or magnesium in the blood, muscle fatigue or strain from overuse, too much exercise, or holding a muscle in the same position for a long time, strain, stress
fracture, tendonitis, claudication, osteomyelitis,
osteoarthritis and Benign tumors or cysts of the femur or tibia and osteosarcoma.
I suggest you to discuss these possibilities with your doctor.
Hope it helps.