"So, you can have IBS and eat fructose just fine if you don't have fructose intolerance? Not everyone with IBS has problems with fructose? They are totally separate things?"
I don't have problems with fructose. I don't necessarily go overboard on it but I don't have symptoms after having some.
"Also, even though I have tested negative for lactose intolerance, I'm not suppose to eat it. Why is fructose different and we can eat it?"
Well, the problem is more that the lactose is in something like milk, which is in general hard to digest because of the amount of fat, other ingredients/proteins that are hard to digest. Fructose can be found in fruit, and may not be hard to digest, like apples.
Once again, I stress the trial-and-error with foods such as fruit and veggies to find out what bothers you.