My 8 year old daughter always complains of a stomachache.  Last evening she compained of a backache as well and this morning she said it is worse.  This morning when she went to the bathroom, I happened to be in the bathroom as well and the odor that her urine put off was very strong and pungent.  It also appeared to be very cloudy.  I asked her if it hurt or burned when she went to the bathroom and she said no, just that her belly hurts a little more before she goes to the bathroom.  I am thinking UTI/bladder infection?
Yes, your concern is very true. This can be a case of UTI. In my clinic, I advise, urine routine, X-ray KU BU, ultrasound of abdomen & pelvis, CBC, renal function tests. You haven't mentioned fever. If pus cells are seen in urine routine, I do urine culture-sensitivity, start with empirical antibiotics & then change according to the reports. Hope this information is useful to you. Regards.