Something tells me you already asked @raising4girls if it was ok to hijack his thread. Perhaps we should start another thread on back pain shortly. Here goes, lol.
Short version, I likely inherited a degenerative condition, and my back problems from my mother. I knew of this growing up, but didn't take it seriously.
I'd injured my lower back several times by my late 20's. Nothing crazy. No more than most people I know of. Just over doing it. I worked with sheetrock in my early 20's, and steel/metals most the rest of my life.
One weekend in my late 20's, I was partying w friends at a local swimming hole. I did some crazy drunk stupid running dive off a tall boardwalk. I landed wrong, it knocked the wind, and shat out of me.
By midweek, I was black and blue down the entire side of my body, and my body felt like it to. It was from hitting the water so hard.
3~ days later, toward the end of the day at work, I bent over to pick up a piece of steel from the floor. It may have weighed 25 lbs. On my way up, it felt like someone stabbed me in the lower spine with an ice pick about 2" above my butt crack. I haven't been the same since.
I was out of work for days, it took weeks to get anywhere near normal. I continued to throw my back out every 2-3-4 months. This cycle continued for years, and to this day. I'm not as bad as I was years ago, regardless, I've got serious problems that that aren't apparent to those that look at me, unless I'm in a blowout period.
When my back goes crazy like this/that, I have an S shape to my lower spine when viewed from the front. Since the swimming/work blowout, I have a permanent S shape, but more pronounced when it's pissed. When it's pissed, I'm as much as disabled. It feels like bone on nerve. Walking, sitting, wiping my a... all are nearly impossible for about 3-4 days.
I had all tests you can imagine. MRI's, x-rays, etc, etc. Worked w a great doctor. He read my MRI's like a book. He could tell where, and when I had taken damage in the past a couple times as well.
I have some scoliosis, and that's been a known since I was a teen. Combine that with a diagnosed soft tissue injury, and I have big problems to live with for the rest of my life. To my knowledge, there is no known cure for this type of injury. I've been told this by many. I'm sure someone would love my money, but a back surgery is highly not recommend.
Where you have "tight", I have some of that. Imagine all the muscles in my back, and core pushing things off to one side to relieve the pressure off the injury. It's even more so when I blow my back up. Just a simple wrong twist can be all it takes. 15~ years later, my back blows up about 2-5 times a year. The rest of the time I'm either ok, or somewhere in-between.
Assuming you are curious, no, I don't have any real correlation between my PvP/s/left ball, and my lower back. About zero "cross talk" as some put it. My body/nervous system/mind has always seen my back, and pvp/s as two separate injuries. Interesting that my pre vas varicocele incident happened 4-5 years after my back injury too. I don't think they are related.
If I have missed something, let me know