my X had the same thing about 4 years ago. she slipped going down the stairs (no, i didn't push her), and had a hair line fracture on the transverse processes(sp?), the little spikes on your vertebra that muscles attach to that allow you to twist and turn. after a few weeks, it mostly went away. 2-3x a year she would get a steroid shot. then one day, completely debilitating. fire pain down her leg, can't move. see dr and say fix asap.
when she fell, the must have damaged the disk, and part of it eventually broke off. to get rid of it, the body surrounds that chunk w/ flesh and blood vessels to make it dissolve. slowly, more flesh and blood vessels. the problem is that this new grown can push against the nerve. and once it's big enough to, then you think you're dying. cut her open, cut out that chunk and excess blood vessels, she's 100% a few days later.