Bad Back

I'm starting to get a little apprehensive about this race I'll be running next month, and not because my training regimen has been less than impressive, but because of my back. A month or two ago I started experiencing a little pain in my lower back following longer runs but I - perhaps unwisely - ignored it since it only happened on a few occasions. Today, however, while at the park with Olive and a few friends, I bent over to pick her up after one of many falls onto the grass, and felt a stabbing pain that hasn't much subsided in the last ten hours. As it turned out, I'd not disposed of the bottles of Percocet and ibuprofen that were prescribed to me after I'd had Olive, so popped a few of the latter (I'll resort to the former come race time if need be), which made the discomfort more tolerable if not completely unnoticeable. I'm just not really sure of what to do at this point. I imagine I'll go to sleep, wake up and feel nothing at all as I've done when my back has acted up in the past, but now I know that this will undoubtedly happen again and I don't want to run the risk of the ol' back throwing me under the bus when I run the marathon (or have running that distance do even more damage; I'll just walk the whole thing if I have to). I feel like I'm too young for this to be happening to me. Do I see a chiropractor now? I'm thinking it might not be a bad idea at this point. It's either that or battle a pain killer addiction, and that's really not my scene.