We are traveling in mexico. we both have stomach aches that have been present for two days now. no other symptoms. what can we do?

If no other symptoms: ...then enjoy the trip & get checked out when you return to California. In the meantime, avoid food & drink at risk, avoid risky behavior, avoid known food intolerances & be very moderate when trying new &/or spicy treats. Seek medical care locally (or cut trip short) if fever, bloody stool, intractable vomiting or diarrhea, worsening abdominal pain.