I have had some back issues over the years and it usually takes 4-7 days before I can move somehow normal. But, I bought a Wahl massage thing, think it was about 40 dollars, blue and think it is over a foot long. I can reach on my own back and a bit down my thighs. If I get in trouble, I massage myself, on the slowest setting and the muscles loosens and I have not had a locked back I think in a year now. And after I got my baby Dodge I can feel that my back is getting stronger and less chance of.locking up.
Bill