Sudden Leg muscle pain. At 11:30 am.

Hi sir, Today morning @ 5:30am my daughter 4.5 yr old started crying in sleep and was saying something was happening to her leg, when I checked immediately her left leg was shaking. Immediately I massaged her leg and make her stand, she was not able to stand and her legs were loose and she was not able to control. Later I make her sit on stool and massaged her leg after that she was ok and was playing actively as usual. Later seeing her active I went to office at 7:40am. When I was in office my wife called me at 8:15 again said her leg was again paining, her left leg became hard and she fell down shaking her left leg and body. She has massaged her leg and within 1 min she was again normal playing as usual. I have came and took her to pediatrician who has said that it may be due to calcium deficiency and prescribed calcium syrup. Again after coming back from doctor while she was playing again her left leg muscles became stiff and she was trembling in pain at 11:30 am.