When I was 19 I worked at a McDonald's on the closing shift. That meant that after we were done serving customers for the day we got to clean up, which paid about 20% more than regular shift workers. One of my jobs was breaking down the shake machine. Ordinarily I have pretty good lifting technique (even as a callow yout'), but the shake mix reservoir was the poster child for awkward burdens (being about 30"x36" and 24" deep), and on one particular night was much more full than I was expecting. I slid it out of the machine and it dropped about 2" to the floor while I was attempting to lift it to carry it over to the sink. Something in my low back gave and I spent the next week immobile, and the following 6 weeks really, really tender. Alls I got was ibuprofen as well, and a note from the doc to my boss that I wasn't to do anything that required lifting or reaching.
About 18mos later I bent down to pick up a pencil (!) and reinjured my back. As I was at school at the time there was nothing to do but suck it up and creak around from class to class feeling like I was 40. Actually, I'm just over 40 now and I feel better than I did then. I had read enough about back pain treatment at the time to stay as active as I could while recovering, and to avoid the temptation to spend all day in bed or whatnot. Needless to say I have spent the intervening years learning and practicing good posture and lifting technique and strengthening the supportive muscles of my low back. I've tweaked it occasionally, but nothing like those first two episodes.