Vaginal pain may be due to the, as you suggested, ovarian cyst, or vaginal infections ( yeast or bacterial infections).
Another possibility is nerve injury.
If you have nerve impingement at your lower back or perineal region, then it can cause pain radiating to your leg & crotch.
If the pain persists more than one more wk., then you need to see your doctor.
Yes, I will still suggest the above possibilities.
Although the fishy smell may be there for long time, sometimes, it may be due to bacterial vaginosis ( although you will not be able to differentiate).
But, neurological etiology as I suggested is a stron possibility if other causes are ruled out.