My housemate was telling me how her younger sister has recently been diagnosed with IBS. However, when she described her symptoms to me this doesn't sound anything like IBS. I know everyones symptons are different. But what do you think?She says she has very violent attacks of vomiting that can last for up to half an hour. She doesn't feel ill at all until she vomits with no warning at all. She says her stomach is very sore after this, and the pain is in her back also.Vomiting is her main problem. The doc is insistant on IBS. Did not go any scope tests, but a few scans?