I have had IBS-d since I was 12 yrs old and when I was in grad school it got to the point where it was so bad that I couldn't eat anything because of intense pain in my stomach. I went to a gastroenterologist and he told me to eat fiber. This didnt help because I couldn't eat anything at the time and so he gave me a prescription for hyoscyamine. This worked a little bit but it made my vision go out of focus really badly and it was hard for me to get the focus back to where it needed to be. So I quit taking it.
My mom was concerned for me and started searching the internet and found this website by a woman who became an expert on IBS because she has had it since childhood. www.helpforibs.com
She sells a fiber that works wonders for both IBS c-d and has a whole list of foods you should avoid in her cookbook.
I bought the book and found it to be helpful although I don't use the recipes. Some of the trigger foods to avoid in the beginning are dairy, egg yolks, pork, red meat, grease, oil, foods high in fat, etc.. and from what you said in your first post, giving up a lot of those trigger foods made it better for you. The good thing about her book and website is she shows you alternate ways to cook, although soy cheese will never taste as good as real cheese, it's worth it to avoid the pain.
She says to focus on how you eat, like don't eat salad before a meal, eat it after. Eat stabilizers like sourdough or french bread before a meal, don't eat large quantities of food at a time etc.
I think the pain part though is to get on the fiber because it has a lot of soluble fiber in it and then figure out what foods trigger your IBS. I found that I can eat pizza from time to time and be ok, but I cannot eat icecream for the life of me. It's wierd.
I wish you luck in your search and I hope this helped a little.