I have a pain in my lower back that kind of feels like a pinching sort of pain, that sometimes progresses to a stabbing pain, it sometimes spreads to my hips and buttocks. there have been a couple of times that the pain is so severe that i have to lie in bed for a few days. i noticed this happens mostly when i sit for a long time or bend in strange ways. i went to a general doctor and he touched my spine and my pain doesnt seem to come from my spine. i'm not sure what this is but i find it very irritating , what can it be?