I have severe discomfort and cramping in my stomach under my diaphragm and in the general abdominal area. no diarrhea. occasional dull nausea ?

Many possibilities: A young adult with tummy pain between the belly button and the ribs' edge can have a variety of problems. A doctor's examination is needed, unless the person is young and healthy, and the pain is mild and resolves quickly. Possible causes include: stomach acid problems, reflux symptoms, pancreatitis, gall stone related problems, abdominal muscle strains, etc... "Severe discomfort" needs an exam.