R., my son had stomach problems, and I mentioned it to the doctor at his physical this week. His stomach had been bothering him a month before. Our doctor tested him for strep, and the test came out positive. We have him on antibiotics to clear it up now.
If you haven't gotten a strep test done, get both a quick strep test AND a culture done (2 swabs). Strep doesn't always present as a bad sore throat and high fever.
Hope he feels better soon!