I hurt my back when I was in college, I don't even know what I did, just one day, my lower back just above the hip was in so much pain I almost could not walk. After a good nights' sleep it was better, but I was still in a bit of pain. I have seen a chiropractor which did not help. I have seen a doctor who just prescribed IB and muscle relaxers. I noticed a few weeks after that first day that there was a good sized lump there, like a muscle knot. Ever since then (10 years) it comes and goes. I notice it hurts the most after I have done an activity that I have not done in a while like ride a bicycle or gardening, or after I have slept badly.
I use Tiger Balm at night, and a hot pack on it whenever I am not moving around much, and do very gentle massage on it when it hurts, this seems to help. I was never diagnosed with anything with a name, that I can remember. Good luck to you all.