I had a uti and was on nitrofurantoin for a week. i just finished the treatment, yet my groin still hurts when i pee and my urine is dark. normal?

No!: Although Nitrofurantoin is notoriously ineffective to treat many uti's, especially if prior antibiotic exposure has selected out resistant GI bugs that cause most uti's, your symptoms reflect a potential complicating issue of urologic stone disease that could be obstructing and can give groin pain when in the lower ureter. You need a spiral ct to exclude a ureteral stone with a repeat urine eval.!