I am a 32 yo female. i have been having episodes of pain under ribs. i was found to have different size kidneys r13.7, l8.8 what could cause this?

Here are some ...: The size discrepancy of both kidneys alone indicates this difference has been lifelong, resulting from congenital - born with it, or acquired, usually related with recurrent UTIs + left vesicoureteral reflux in childhood. Based on these, your local urologists should be able to discuss with and counsel you for the future to follow.