The spine, being made up of 24 fragile bones and associated cartilage and tendons, supports the whole weight of the upper body.
Due to the complex nature of the spine it is advisable to consult your doctor if back pain persists for more than a few days.
If the pain has been caused by abuse, such as lifting heavy weights, be sensible and take things easy.
Take care to sit as upright as possible with a support for the small of the back.
Take aspirin or paracetamol, which will relieve the pain and help to relieve inflammation.