I think we can rule out "disfunction." Prior to my calf injury (see my martial arts experience post in the General Discussion) I began experiencing back pain. The sports med doc. concluded there was nothing functionally wrong and that my aches were the result of fatigue. I stopped my back exercises (back extensions off the couch, 3 X 25-30, twice a week, plus TKD) until the aches disappeared and my back felt normal again (this took between 2 and 3 weeks). I stopped going to TKD due to my calf injury, which helped too. After the aches subsided, I re-started my back work, returning to back extensions on the floor, doing 3 X 15 on 90 seconds rest. I've worked my way up from there (conservatively), and with the past two days as an exception, my back has felt fine.
My hamstrings felt fine for 8 weeks. (I began posting my workouts in week 7 of my workout plan. I'm currently in week 12.) In week 9, I increased the weight for lunges from 0 to 10 lbs (see posts for Week 3: Sunday 10/12 and Tuesday 10/14). I believe this is what started my hamstring issues. For now, my thought on the slow hamstring recovery is that it is not related to my back. I just increased the weight for my lunges too quickly.
For now, I'm going to reduce the lunge weight back to 0 and reduce the reps to 20. I'll work my way up to 30 reps and then add 5 lbs. For back extensions, I'm going to reduce the reps to 3 X 20 until I get used to the back extension bench I'm now using. If the hamstring recovery doesn't improve, I'll reconsider going to a chiropractor.
Although my hamstrings feel fine today, I'm going to wait one more day before I do another leg workout, just to make sure.