I'm traveling around se asia and i have had a major headache (unusual for me) and stomach pain. no other issues. ideas?

The main ideas: include mild gastroenteritis (stomach flu), dehydration, sun exposure, and/or diet change. Be sure to get enough water and rest. You'll need attention for bloody or black/tarry stools, nausea, persistent fever, rapidly worsening stomach pain, vision problems or dizziness with headache, rapidly changing headache or one that wakes you from sleep.

Possible virus: These two symptoms are often prodromal of a viral infection which may localize to the respiratory or gastrointestinal tract in the next hours. However,since you're in a foreign country,I recommend that you get examined by a physician unless you're feeling much better soon. Take TYLENOL, (acetaminophen)eat a light diet,drink adequate amounts of fluid and rest up in the meantime.Don't delay if symptoms worsen.