I have used an inversion table for years. Now and then, I get a back pain at L3/L4 and the inversion relieves it immediately and for several days. Takes only a few minutes and I don't have to hang all the way upside down.

Recently I've had abdominal and thoracic surgery for several cancers and have been forbidden to use the inversion table. (I am not allowed to ride my bike either but I do, in moderation.) The back pain has returned and I have to live with it.

I've tried lying flat in a yoga back relaxation exercise and it works somewhat. There's a book called Yoga Back Book worth a read.
https://play.google.com/store/books/...d=LevCQYFvzcMC

Here are some other gadgets. Top 10 Best Back Pain Relief Products That Really Work | Back Pain Health Center

Nothing I've tried works as well, quickly and long as the inversion table.