Nausea and constipation. Please suggest.

Hi Doctors I have a question about my daughter who's 7 yrs old. Few months before she had a mild pain in the right side of her abdomen which was so mild. I went to first doc.. He took US and told appendix inflammation not seen... But to be on the lookout. 2nd time I asked for second opinion from another doc after a month as her mild pain was there still.. Another US was taken and they also said everything is normal. And a month later she stopped having pain there but a mild bulge was there like a fat skin so 3rd US was taken yet still normal. Now weeks after this US scan she is complaining of nausea....and has mild constipation. Should I check for CT as suggested by her doc or shall I request for an MRI or should I wait. She complains of mild pains around tummy and near chest ( which was also checked in early checkups) please suggest Otherwise of the mild pain and nausea that she is complaining.. She is normal and active. Please suggest.