Can an mri-us- or ct scan see if there's something in my kidney or something. i have this constant dull right side pain. right on the side though.?

Yes: But uncertain what you have already had done. Usually would want to start with a history & physical exam with your doctor & blood & urine tests. The locations of pains do not always indicate which organ may be the cause of pains. Ultrasound can see organs, and sometimes a ct or MRI may be better. Each person's conditions may indicate which testing is best.