I was diagnosed with Crohns about 7 years ago. I had severe blood in my stools and was sick when I ate. I believe that every individual case is different. I have found that all drugs and meds have side effects that are not worth the trouble. I stopped seeing my doctor after the first year and decided to do my own research and study my own body. I have found that stress can bring on a flair up very quickly. I have also found that an empty stomach can bring on a flair up. I try to eat very small amounts of food every three hours or so. I have also eliminated processed foods as much as possible. Organic is ideal, although not always possible. If you analyze your diet and stress levels, I believe you can get this under control. It's not easy, but it's very worth it to get your life back! Doctors are great, but this is one of those things they don't yet know enough about. Surrendering to drugs is not the answer. If I eat anything raw (it's an accident when it happens) I need cipro. Otherwise, I am doctor free!
You can certainly see Crohns disease of the stomach. In fact, it can affect any portion of the gastrointestinal system from lips to anus. Your symptoms may relate to stomach involvement but would also be consistent with a partial obstruction or narrowing of the small intestine which would be more likely. A contrast study such as an upper GI series with a small bowel follow through would usually be done to evaluate these possibilities.