Right flank pain. Ct w contrast about 2 weeks ago revealed growth of a cyst on the l kidney. R kidney was ok I guess. What could this pain be?

See below. The pain in the right flank unlikely to be related to the kidneys or cyst. Also no stones were detected.If you have a history of stones , may be you passsed the stone.
Lots benign. Flank pain can be from many things including, dehydration, infection, kidney stone, stress, muscular strains, bruise or trauma, sciatica and nerve impingement or bulging disc, gas, constipation, reflux, etc... With a negative ct scan on that sign recently, there shouldn't be concern for cancer.