Hi We travel to Philippines June 24,2017.while on the airplane my son has fever (38.9) that fever last for 6days,after his ok and active.we came back here in California July 11,2017.my son seems fine and active.july 14,2017 when I came from work I check my son and he has (102.5)temperature,I gave him Advil and the fever gone after an hour.my son is turning 9years old this coming September. The fever is on and off and it s been 12 days.we keep on going to his pediatrician and did a lot of test and i also keep on bringing him to ER and they also did a lot of test including malaria,X-ray Urin test etc.but all the result is negative.yesterday I bring him again to his pediatrician coz my son complain that his left neck on his lower ear started having pain,his pediatrician prescribed a antibiotic. I hope u can help me coz I m worried and don t know what s going on to my son coz the fever still and and off till now. Thank u in advance