Gallstones...

 Thanks again everyone.  So... he actually was worried enough to go to the ER this afternoon and get an ultrasound.  They said they had some difficulty imaging his gallbladder, but also said they didn't seen any stones.  So.  They suggested he might have "gas" or "may have eaten something that didn't agree with him."  His bloodwork showed nothing abnormal, either.  

Seriously, what else could this be?   It's really distressing.  He's terrified to have that pain again.  The surgeon is out of town, so his on-call person will see him tomorrow.  I'm assuming they'll probably send him for an endoscopy.  

In addition to a protein shake, he sliced turkey breast with a little lowfat mayo and a slice of cheese for lunch with a 1/4 of a banana.  He's been ok since.