Studies show many different kinds of people with various jobs develop a disc problem. Most are involved with heavy-duty work, but some have light-duty work or are students or retired.
Heavy lifting and repetitive movements put a person at increased risk of back injury. Smoking or tobacco use are also linked with low back pain. Aging with disc degeneration is also a risk factor.
Even though your situation seems like it happened all of a sudden, it's likely that a gradual process of disc degeneration has been taking place over time. An old injury, poor posture, or large abdomen adds stress and strain to an already aging body part.