When I've worked at it in the past I could touch my toes but not now. I used to set the top of the bar 4 inches below the saddle, now it's an inch or 1.5 inches. Had a couple back injuries but the main issue is my neck. Still doing club rides and I'm usually the slowest so I need to get in the drops which isn't a problem except for the neck.
Lower back hurts sometimes on extended climbs but it doesn't hurt if I have been climbing a lot.