I was interested to see this discussion. I have had back issues for the past several years Mine usually show up as a kind of cold stinging pain into my thighs and groin rather than back pain. I have had some epidural injections and once had a disk ablation. I am 46 years old now, 73 inches 225 lbs. Anyway, I started recently working out with new mountain bike build to be away from cars while riding. Mine is a steel hardtail by Niner. I have started to have some of the pain I have had in the past. I hope it isn't the pounding and the slightly curved position of the low back causing it.