lumbago

Backache of the lumbar region or lower back, which can be caused by muscle strain or a slipped disc.

Sir Oswald Feiling winced as he turned to go home. He had felt a warning twinge of lumbago.

We may imagine an athletics coach with a scientific training researching into the physiology and the psychology of runners. [...] He finds out the effects of fatigue, of alcohol, of tobacco, of lumbago and of depression upon their performances.

An episode of such backache.

To affect (someone) with lumbago.