I hope your son feels better today--poor thing! Yes, these triggers can cause that much pain. I have been to the ER with pain so bad I could barely walk or breathe and such an attack can last for a few days. Unfortunately, I don't have anything for the pain other than heat pads and peppermint tea; I have been given anti-spasmodics before but they didn't help much. I'm not sure what is available for children. Have you read Heather's The First Year: IBS? There's quite a lot of information in there about children with IBS.
For me, dairy is the worst trigger--and it's not just the lactose but the proteins in milk that make it difficult to digest. Plus, most dairy products are also high in fat--so you get two triggers in one! Avoiding dairy and the other triggers listed on the main site will help you and your son manage his IBS and the pain. Here are some useful links and posts about triggers and how they cause attacks and Heather's very accurate description of how IBS pain feels:
Posts
Re: not lactose intolerance, but dairy?
Yes, these triggers can cause that much pain. I have been to the ER with pain so bad I could barely walk or breathe and such an attack can last for a few days. Unfortunately, I don't have anything for the pain other than heat pads and peppermint tea; I have been given anti-spasmodics before but they didn't help much. I'm not sure what is available for children. Have you read Heather's The First Year: IBS? There's quite a lot of information in there about children with IBS. 
Take care.
