More and more studies show it doesn't matter how some kinds of back pain is treated. It goes away in about the same amount of time for everyone. The use of painkillers has been called into question because of these findings. Doctors may prescribe drugs when patients insist on taking something, and other medications have been tried.
Likewise, X-rays don't show much when the cause of back pain is unknown. Efforts to reduce costs of back care have resulted in fewer X-rays being taken. The use of MRIs (magnetic resonance imaging) is on the rise, but it's not clear whether these show any more than X-rays in cases of general back pain.
Some doctors suggest a "wait and see" approach. Use painkillers, rest when needed, and activity at all other times. Pain that doesn't go away or gets worse can be further investigated with more expensive imaging studies. A trip to the emergency room is not usually cost effective. You're better off sticking with a doctor who knows you and your case.