Have been feeling a dull stomach ache for three days. i use 10mg prilosec each morning and use heaping tablespoon metamucil after dinner. causes?

Need more info: There are dozens of things that can give you a stomach ache. Need to know age, sex, other medical conditions, etc. Unfortunately, i can't narrow things down for you. My guess is that any acid reflux is being treated with the Prilosec (although that is a low dose) and you are regulating your bowels with the fiber. More testing is likely needed but see a medical professional so they can focus test.