I too have a gal of 3 yrs and now a days she is saying...she is tired and asking us to carry her all the time. Make sure she is drinking water properly. Now kids will be either walking or standing.. they don't sit when they are active. Make her take rest every now and then. Just ask in her school ...she may be doing cycling or other activities. Heat coconut oil and after removing from stove.. crush camphor in your fingers and add slowly to lukewarm coconut oil. then apply on her legs.. this will give relief. Alternatively...you can use " Karpooradi tailam" from any ayurvedic shop.

Pls consult dr. Im sure its just a little bit of vitamin need. Thats all