Creeping Backache

Your back never used to ache picking up a box of books, or sitting at a computer for hours, but over the past few weeks you're noticing a gradual increase in discomfort. Is there anything you can do? Should you do something now, or "stop whingeing and just get on with it like everybody else" ?

Is it old age?! (I remember wondering this at the grand old age of 28!)