There are a variety of reasons for RLQ pain. I agree with the CT scan, which would exclude
appendicitisAppendicitis. I would also consider
inflammatoryInflammatory bowel disease
Ulcerative colitis bowel disease, such as Crohn's disease, as well as irritable bowel syndrome.
A colonoscopy would be a reasonable next step, and if negative, blood tests can be done to evaluate for celiac disease.
Adenitis by itself is less likely to lead to the abdominal symptoms you are describing.
These options can be discussed with your personal physician.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin Pho, M.D.
KevinMD.com
Twitter.com/kevinmd