Mate, had a similar injury on my lower back, pissed me off so much because I hate to take months off training, and even after the chronic pain went away, if I did anything too harsh the injury would flare out and then go away after a week or so.
I would say seek medical attention if you can afford it.
We have free healthcare in the UK, but it's as good as shit, because it's under resourced. So they just tell you general adivice, like fix your posture, don't strain it too much with the injury and go for walks/swims, as it seems to do really well for the back.. Which is good advice and all you can do for the time being.
Most back pain will go away over time, but in future take preventative action.
Do magnificent mobility, the excercises will stretch your back like you didn't think was possible.. and is very relaxing as well. DO the stretches before the workouts (they're dynamic so very good pre workout).
and also do foam rolling, or tennis ball rolling for the back.
Check out the 3 links on lower back pain on this page
http://www.aboutstrength.com/2010/01...back-problems/
I injured the exactly same part as yours, about 2-3 inches to the left of the spine, above the belt line. In fact my spinal extensor [I think that's what it's called] is smaller (and weaker) than the right side.