I have been playing graphite shafts then switched to steel and now it seems my lower back hurts. Is this just coincidence?

I really wouldn't think so. Are the clubs heavier overall?

Have you practiced more since the switch? I always insert a shock dampener in steel shafts before the grip install.

No more practice but shafts are heavier

I'm 45 and switched to graphite shafted irons a year ago. Everything tends to hurt less

I'm 38 and have had 3 back procedures. Went from graphite to steel a few years ago. Instant feedback, it hurt after a round. Went back to graphite. Still sore, but not like the steel.

I liked the steel, got more spin, went back to graphite, better launch and distance, not as much control. Don't care, I love the graphite