My son has a fever of 103 he is 5 years old is it normal?

Of coarse its normal. Little kids ages 3-7 years of age hang around with germy kids at school or even home. One kid may have a cold then sneeze on a toy then put it down and play with another toy, then your son may come up and play with that same toy, getting the germs on his hands then touch his face spreading the virus. So you shouldn't worry this happens all the time.