Emotions and activity can play a big role.
I have noticed that I tend to have more gas after being stressed (have you been tracking that?), or if I have been doing a lot of physical activity like exercise or house work which can also get things worked up in the digestive tract. I also noticed, too, that my IBS symptoms seem to get worse with hormonal changes like when my period would be due (I am peri-menopausal, on Depo Provera and periods are merely spotting and staining for me now).
If you cannot find a specific food trigger, and if you cannot link it to emotions or physical activity, you can get on medications (
Zelnorm is the only one that comes to mind right now).
My husband eats whatever he wants whether or not it gives him gas or heart-burn. He just controls it with Tums.
Good luck!
Lindaru