Pain In Lower Left Side

I've had this pain in my lower left side, more toward my back. I first felt it right before I started my period, so I assumed it was either a cramp or a cyst as I've had both before. It's been about a week since I've had my period and I still have that pain. It's gotten to the point where it hurts to put weight on my left foot because I feel that stabbing pain in my side. I'm not sure if I should get this checked out or just wait it out, but it doesn't seem to be getting any better on its own.