I have an 8 year old girl 72lb. she is hurting low, hurts low when she pees. can i give pyridium (phenazopyridine) till we see the doc later to ease her discomfort?

No. Her MD may : prescribe Phenazopyridine at 4 mg./kg./ day divided into 3 doses, but it can cause false results for sugar & ketones in the urinalysis that the MD needs 1st. Overweight girls get vulvitis from entrapment of urine after voiding & can get a UTI from wiping back to front, leaving normal fecal bacteria to overgrow there. Have her sit backwards on the toilet to pee & wipe front-to-back when done.