My 16 mo old son wakes up from naps, screeming and crying for 30-40 min. tried pain meds before nap and snack, no difference. what is up?

Call your doc: Call your pediatrician. Your child should probably be evaluated. Also call your doc before giving pain meds to children younger than 2... Especially for abdominal pain (call 24/7; the practice should encourage this).

Depends: How long has this been occurring? Are there other symptoms? Is the toddler healthy? See your pediatrician to look for an explanation.