As you get old, this may come with feeling some pain in the lower back. This is because the discs in the spine, which act as cushions between the bones have become worn out. And they don’t repair themselves because not enough blood gets there. But you don’t have to be old to experience back pains when you sit down, it could be all due to a muscle strain brought about by bad posture. Or a herniated disc. This is when a disc in your spine has been pushed out of its normal shape. This can be brought about by natural aging, a fall, or lifting heavy objects improperly.