What do you suggest if my son ate beef burger and with in 6 hours had six watery diarrhea, then got extreme chills and fever 104.5 f?

Food born illness: This sounds extremely suspicious for a food-born diarrheal illness. Many times these are bacterial, but even so are often self-limiting. I would encourage you to get a stool sample collected for culture, including toxigenic E.coli, and have doctor order to get those incubating. It takes 2-3 days to get results, and by then you'll know if son getting better or worse. If sicker sooner, go to ER.