It certainly could be. Although growing pains occur mostly in school-age children, they can also happen to younger kids. Growing pains are marked by discomfort in both legs that tends to come and go. They're usually caused by the muscles in the legs being too tight to stretch with your child's growing bones. This muscle pain can cause spasms, which tend to last a few minutes at a time. Flexing the foot and toes upward often relieves the muscle tension, as can gentle massage and a heating pad applied to the area. Even though growing pains are totally harmless, it's not a bad idea to have your daughter checked by your pediatrician, especially if they awaken her from sleep and occur in only one leg. In very rare cases similar pain can be a sign of juvenile arthritis, which would require anti-inflammatory medication to treat.