Just last month, after doing squats in the gym the very next day at work, ( fed ex ) i bent over to lift a heavy box and i felt a pop in the same place u said, lower left back right next to the spine. Along with the pop was numbness all the way down to my feet. Went to the hospital and they didnt do shit, told me it was a sprain'd muscule. Went to my Doc. and she sent me for a mri. which thank god they found nothing. Took Flexeril for about 10 days and with 1 week rest out of work, a heating pad and 2 weeks on light duty, i am finally back at work and have been back to the gym 1 1/2 weeks but going very light for conditioning... The outcome is it was pulled muscule, close to the spine. It felt alot worse then what it was..Def go get a mri done then youll know from there.... I feel for you bro..