Re: Back pain .... strange snap sound...gone
I'm a retired pilot, not a doctor, but I have written quite a bit on this forum about backs. It's difficult to guess what happened to you, as discs don't move per se. They sometimes herniate, but I doubt that's happened here because of the spontaneous recovery. I would guess that you somehow moved a vertebra--relative to its neighbor–in a way that caused one of the facet joints to jam out of its normal range. Understand, this is just one of dozens of possible scenarios, I couldn't possible know the facts. Because of ageing, the sciatic nerve finds that it can not travel laterally far enough to allow for this displacement. (Typically 4mm) and this may mean that it was pulled tight over a surface rather than having enough length to slip along it. When the joint happily unlocked, the nerve would be relatively unscathed.
So often people will be told that they have a slipped disc, this is just a way of saying that the back is out of kilter in some way...this coverall term is as good as any, cos without careful investigation, nobody knows what's happened in there. A doctor or a real chiropractor / osteopath will have been trained to recognise the areas of the leg or feet that are affected, and be able to make a better diagnosis just from this information. So often these folk can give immediate relief, but in the case of an annular tear in the disc, it can be made worse. It's a difficult call, and that's why doctors so often choose not to recommend manipulation too soon.
More often than not it will get better by itself, and it sounds as though you may be lucky, but do take care...great care, for the next 12 months. You need to make sure that you keep your back strong (-ish), without risking a reoccurrence. Making a very cautious increase in your daily exercise will protect you from many problems in the future--providing that there is nothing really wrong. There is a plethora of opinion on how to do this, but whatever you do, do something, and do it carefully.
If it happens again, insist on an MRI, it's the only true way to know what's going on.