Varies but i have known it take over a week. I will take pain killers and try to do a lot of walking which is natures way, but if it doesn't improve quickish I'll get my "Calanetics for your Back" book out and do the exercises twice a day.
Last year I tried to find a chiroprator but there is only one some distance away and he/she was away on holiday. so I went to an osteopath and her stand-in had a go. I was nowhere near as bad then as I am now but it was in an annoying place and stopping me from working with my right shoulder. What she did though weird seeming to me, did in fact help it a lot.
The pain today is much worse and debilitating but i recognise it and know how to deal with it. In the UK one session, possibly two, with a decent, strong chiro sorts me out, but it has to be a strong man or woman, (never met a wimmins yet who can do it!) They perform a special manoeuvre it all cracks and whoosh, I'm off again. The dodgy vertebra(e) is/are just simply put back into place.
The problem is how I did it in the first place. (1972) If I had done it the conventional way, i.e. by lifting too heavy a weight awkwardly, then it would be easier to fix.
But thanks for asking!