Pain, Actually Feels Like A Bad Cramp Is About To

Pain, actually feels like a bad cramp is about to declare itself, but not fully kicking in. It is lower than the tailbone, almost at the bottom of the buttocks, left side only. Off and on briefly for about 5 days, but persistent today and beginning to periodically radiate with a tingling sensation down my leg. If I touch the floor from a standing position it momentarily seems to aleivate with the stretch. Do I need to be concerned?