Ratsbuttocks, definitely a case of prevention is better than cure !
Try and get hold of your firm's "lifting and handling" policy, it's usually tucked away on a dusty shelf. It will contain load's of advice about correct lifting, posture etc.
Backs usually start giving you problems after years of abuse.....some other tips, keep your weight down, and strengthen the ligaments around the spine....swimmers, apparently, rarely get back pain.