I don't, however, second that.
Don't get me wrong, I'm the guy in the gym that everyone gawks at and goes "Why is his ass touching his ankle? That can't be healthy?!"
But i also know that for all of my highschool football career, i basically did front squats and deadlifts (sumo stance), and it all transferred over into my back squat.
OP, DO BACK SQUATS. But, if it hurts enough, (as it did for a large portion of my life due to lower back issues from football), then start with front squats.