Having a large belly causes imbalance and to compensate for this and to prevent toppling forwards a person will lean backwards. Weak abdominal muscles may also be partly responsible for lordosis developing, as may having a poor posture. In fact, having a kyphosis may contribute to a lordosis developing as well. Once again it's about trying to correct the imbalance created by the excessive outer curve. Both these excessive curves of the spine can cause muscular strain and muscle aches.
Physiotherapy helps to strengthen the supporting muscles of the spine and correct poor posture.
Where there is an underlying cause, for example osteoporosis, then this needs to be treated. Maintaining an ideal weight is also advisable if further problems are to be avoided. In the normal spine there is no sideways curve. When the spine does curve to the side then this is called a scoliosis. A scoliosis most often appears in the upper chest area or in the lower back and usually there is no obvious cause for it.