Lots of people have trouble with soy products. Some even have intolerances to soy. I'm not a vegetarian (but very close), but see if eliminating soy for a while makes a difference. For gas, fennel tea is wonderful. Crush up a tablespoon of fennel seeds and steep in a mug of boiling water. Drink several cups a day. This may help too. Also, in the YOGA for IBS at the LEFT hand side of this page has a wind relieving pose you may find helpful. I find it really "clears the air" if you know what I mean LOL!
-------------------- Formerly HanSolo. IBS, OCD, Bipolar, PTSD times 3.