Three herniated discs in my back causing sciatic pain. It wasn't that the pain was bad on a moment-to-moment basis, but that it just want on and on and on. It was agony to sit down, so I had to stand in my cubicle to work. It was painful to lie down, so I ended up getting about 4 hours of sleep each night. I was taking several grams of ibuprofen, acetaminophen (yes, I'm lucky I didn't destroy my liver), and naproxen sodium daily, just to be functional. This went on for over a year.

The fun part is that when I first starting having sciatic pain, I was pretty sure that it was my back, because I hadn't done anything that would have injured my leg. I had really good insurance at the time, but my doctor refused to order an MRI or even an x-ray; he thought I was trying to get a prescription for drugs. It took about 15 months of pain, and multiple visits to my doctor, an ER, and even attempting to see a chiropractor (who was at least self-aware enough to realize that he shouldn't touch me without an MRI first), before a scheduling error got another doctor in the practice to look at me, order an x-ray, and then order an MRI on the basis of the x-ray. Within about two days of the MRI being read I had received a referral to a neurosurgeon, in less than a week he was asking me whether I wanted a laminectomy or a spinal fusion. (These days I'd be opting for disc replacement), and I was recovering from surgery about a month after that MRI.