My stomach has been making a lot of growling noise, passing a lot of gas and having upper stomach pain for 3 weeks. no blood in stool or vomit.

Possible IBS: You can possibly have irritable bowel syndrome. You would have to see your PCP for initial evaluation and then possible a gastroenterologist for testing. There are medications that can help your symptoms.

IBS vs. Giardia: This could be IBS but need to check for Giardia as well. Have you been traveling? Would see GI doctor soon.