I took x rays for low back pain and it came out normal, but i still have immense pain when i am sitting down for a long time, working out and other simple daily activities. would it be helpful to do an mri or any other type of scan?

May be: That depends on the ordering physician, better see a spine specialist, a neurosurgeon or an orthopod specialising in spine problems, who can direct your care after evaluation, good luck

Yes: 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 in the spine, kidney, or elsewhere; fibromyalgia, etc... With such a long list of possibilities, one's doctor examines again.