My six year old son woke up this morning with a fever of 100.6, and began vomiting mostly clear liquid. Now, after 8 hours, his vomiting has subsided, but he is complaining about his leg hurting about halfway up his calf on the outside. I thought at first it s probably just a muscle tensing up from laying around most of the morning so I had him get up and walk around. This didn t help, so I had him sit while I moved his foot back and forth to see if would stretch out. Nothing. I grabbed a heat pack and placed it on there, and it distracted him a bit, but then he said it was stinging and started crying again. I see no evidence of anything external. He s never had chicken pox , and is up on vaccinations. Any ideas?