I'm certainly no doctor, but it definantly sounds like parasites,from the smelly stools, gas, etc.
Have no idea about the constant movement-never heard of that. Probaby some sort of side effect from the vaccines he had and from the Paxil you were on during the last months of your pregnancy.
Maybe it would help him to do some sort of cleanse, maybe liver, parasite, and metal-he probably has a lot of toxins built up it sounds like!
I wish you the best of luck-sorry I couldn't be more help though!