I have been suffering with the EXACT same phenomenon for the past year and typically notice that it gets worse or better depending on diet and exercise. When I eat dairy or nuts, or when I remove or stop drinking coffee or do a sugar detox these things will all trigger the pain--inflammation caused by these foods or the abrupt removal of these foods will sometimes cause my back to seize up, usually when standing, but always when I twist slightly the wrong way. Thing is, I can pretty much bounce right back and be fine. Run, jump, stretch, whatever. When I am eating clean for months at a time--this doesn't happen. Remember your colon is back there too!

I believe I have also compromised my lower back by doing indoor cycling for so many years. The lack of back support on these kinds of bikes is notorious for causing lower back issues.

I want to also say that I do not incur ongoing back pain, enough to warrant taking drugs. My back seizes up randomly, and then I'm fine. No pain.

I hope this sheds extra light on your situation. I know I would not want surgery at all. And that's kind of what I fear if I go to a specialist for this.