s11 started throwing up. It happens every once in a while due to post nasal drip. He will throw up for several hours and then be perfectly fine.
Umm.....GB.....I'm gonna play "I doubt it" with this diagnosis. Kids don't usually throw up repeatedly from post-nasal drip. Once in a rare while, maybe, but not repeatedly like this.
What this COULD be, instead, is either Cyclic Vomiting Syndrome (look it up on cvsaonline dot org) or a migraine equivalent (not all migraines have headache).
I recommend you find a doctor familiar with these diagnoses and get him further evaluated.