My Daughter Has Been Needing To Sit On The Bathroom

My daughter has been needing to sit on the bathroom frequently, but does not always need to go. We took her to the doctor about 2 weeks ago to check for a uti, but results were negative. The past few days, her urine has had a more distinct odor. Is there something more I should be worried about? Also, we do baking soda baths twice a day, but that has not seemed to help. Could it just be in her head?