I went to lie my 2 month old on the bed for a change when i got intense lower back pain. it's where the back meets the hip/butt area now it hurts to move sit lie down or stand i have had back pain of and pin since the labor back in nov. what did i do?

Doctor can examine: Maybe something shifted in labor. The more common causes of lower back pain include: back muscle strain, back ligament sprain, fractured vertebra (spondylolysis), slipped vertebra (spondylolisthesis), herniated disc, spinal stenosis, spinal arthritis, urine infection, kidney infection or stone, tumor, fibromyalgia, etc... With such a long list of possibilities, one's doctor can examine.