My symptoms were:
Pain across the diaphram and, after about 5 years, pain on the right side--including the feeling of a lump under my rib cage. Aching pains in my right shoulder and down my right arm into the elbow. These pains were not constant, but came and went seemingly at random. I also suffered from "attacks" which was a sudden onset of very bad pain, nausea, and finally explosive diarrhea.
Diarrhea with and without pain. Yellow in color (from the bile, although it can also manifest as green), and it burned and burned and burned. The more D I had, the yellower my poops/water became and the worse I burned.
Sudden bouts of nausea, even in the absence of food. I only vomited once, but vomiting is usually a fairly common side effect (I had more D and less vomiting than many). In fact, vomiting is not considered a side effect of IBS, although it does occasionally happen to some people who have true IBS. Feeling suddenly stuffed and uncomfortable, even though I hadn't even finished a normal-sized meal. This is a very common symptom.
When I was nauseated, I couldn't lay down because it made the nausea worse. It also made the pain worse if I was hurting.
You can have nausea and indigestion problems in absence of vomiting and diarrhea, although you have to be more careful to check to make sure you don't have an ulcer, hietal hernia, slow-emptying stomach or acid reflux problems, as these all have very similar symptoms.