Working through some lower back issues

The injury cycle I mentioned in my previous post included, among other things, some lower back issues that impacted much more than just my running. Unfortunately a bit of that returned last week, but fortunately it was not nearly as bad as before and at this point I have it under control. My torso is very long compared with the length of my legs. I'm 5'10", my dad is 6'1", my mom is 5'0", and I joke that I inherited my dad's torso with my mom's legs. I'm not built like a runner at all. I've had lower back problems since my early teens, when I first hurt myself lifting weights with bad form (it happened other times later as well). But I think the lower back issues I've had as an adult are mostly or entirely related to poor posture, aided perhaps by my odd proportions. My chiropractor tells me I have a curve in my spine that is not supposed to be there (front-to-back, not left-to-right as in scoliosis). When my back locks up it does seem to be in the area where that unwelcome curve is located. I have a gadget called a posture pump disk hydrator that I use to straighten up that curve and coax those muscles to loosen up, or to discourage them from locking up in the first place, and you can do basically the same thing with a foam roller. Anyway, my back tightened up on me last week on Friday (June 24), the day after a long run. I don't think it's caused by running, but rather my posture tends to be especially bad when I'm tired after some long or hard runs. When my back locks up, running can initially help to loosen things up. So I did an easy run after waking up with it tight on Friday. Then on Saturday I planned to run easy again at the Parkrun but ended up running at tempo effort for 5k. That was probably dumb, but it's difficult to restrain myself when running with others who are putting in effort. I took the following day, Sunday, off as penance. Over the next couple days, on each of which I ran easy, my back loosened up enough that I was able to hazard a workout on Wednesday. It felt almost normal before the workout but did tighten up again somewhat afterwards. So I did a recovery run the following day and then took another day off. By Saturday, July 2, it felt pretty much fine again, but I didn't want to risk it tightening up from running faster. So I skipped the Parkrun that weekend but did a long run on Sunday. I'm writing this the day after that long run, and my back is still fine. In spite of these back issues I was able to run 55 miles this past week, which is my highest weekly volume yet this year. Assuming my back cooperates, I'm planing to keep it there or inch upward very slightly next week and to return to the Parkrun next Saturday.

 June 20-26:
Mo: off
Tu: 3 x (3, 2, 1 min.) with half recoveries
We: 7.5 miles
Th: 16 miles @ 7:34/mi.
Fr: 7.5 miles
Sa: College Park Parkrun 5k in 20:07 (6:35/mi. pace)
Su: off
Week total: 47.7 miles

June 27 - July 3:
Mo: 7.5 miles
Tu: 8 miles
We: 3 x (1, 2, 3 min.) with half recoveries
Th: 7.5 miles
Fr: off
Sa: 8 miles
Su: 15 miles @ 7:39/mi.
Week total: 55 miles