What couls be causing pain in my left lumbar region?

Several things: There are nine structures i nthe back that can cause pain: the ligaments, muscles, bones, nerves, joints, joint coverings(capsules), disc, disc covers(annulus) and skin. So, what brings on the pain and where it is(middle of back, one side or the other, etc.) helps sort that out. Early on, in the first six months, it is uncommon to need any x-ray or other image study. The best bet is a good exam, .