When should i see a doctor about persistent lower back pain?

Now: Proper diagnosis is ABSOLUTE KEY to proper treatment.I recommend exam by a dr. skilled in hands-on osteopathic diagnosis & manipulation.Since pain could be caused by anything from disc injury to QL spasm, SI inflammation or ligament injury, acute SI or lumber vertebral dysfunction, to more serious cuases, etc.-someone who can truly differentiate cause can give you the best answer.