Sounds like a very mild case of crohn's or related IBS conditions, they usually come with gas and stomach noises. But since there's no pain, it could be just the way your digestive system works, polyps are fairly common too.
I don't think that you'll have any trouble with SN, aside from a slight painful feeling depending on how sensible your stomach polyps are. I think I remember some members talking about similar conditions and still succeeding with SN, but keep in mind, there's no telling if they actually succeeded since those experiences are not verifiable.
Unless you have a VERY bad and debilitating gastric condition, then I don't think that there's any problem with SN. But don't do a test run or a small trial, this substance is really toxic and even lower doses can cause some very uncomfortable effects that could lead you to the emergency room. It has happened to many people here.