That's actually a classic IBS pain pattern. I know C's get alot more general pain and discomfort than D's....and of course everyone's different!
Double check the Jacks, I may be wrong. If you can't eat regular pasta, I'd be suspicious of a wheat or gluten intolerance too. Maybe you should do an exclusion diet? DOing it for gluten is pretty tough tho as it's hidden in so many things and some people say it takes 3 months to readjust...but at least you might then know.