Back Pains are often the result of muscle spasms. What causes these muscle spasms is not clearly known. It could be due to stretching too much, carrying a heavy object improperly or mental stress. Most of the modern day maladies are Psychosomatic.
Back pain normally affects people who do not move about much.
The pains are sharp shooting pains and the inability to move in certain ways.One should always consult one's physician, if the pain occurs frequently, more than once a month. It is not something to be ignored.
In order to avoid the occurrence of pain, one needs to follow some posture and movement changes..
Maintain an upright Position
People going through the pain, often feel like lying on their back .But if one is keen to get relief from the pain. One should be in an upright position. Spasms often last longer if one is not moving around.
Gentle Movement
The spasms take time to subside, so there should not be any jerky movements, during that time. If bending and twisting gives rise to sharp pains, one should avoid such movements. Walking in an upright posture is important. If spasms hit you, when you are lying down, roll on your side and prop yourself up, using the support of your arms.
Choose Your Activities carefully
one should not take part in activities that involve picking up something by bending down. It is better to squat and pick it up. While doing it keep your back straight.
Sitting For Long Hours
If one has to sit for long hours, while at work, using a stability ball as a chair can be a great idea,to relieve back pain. 

Some Exercises for Relief of Back Pain

Abdominal crunches strengthen the abdominal muscles and that may reduce the incidents of back pain. The pelvic tilt is helpful, in tightening the back muscle.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Standing at arms length away from the wall and by leaning one’s lower back towards the wall is great for lower back pain.Lean in as far back, as you can becaue this will stretch out your vertebrae and can put them in alignment.

As you go about your day to day activity, suck in your stomach and tighten the abdominal muscles and hold. This helps in strengthening your abdominal muscles, for better posture and support.

Try to wear flat shoes with heels of only 1”. Higher heels normally put strain on the back.

There are also medicines available over the counter, which give relief, but there are sometimes side effects, associated with these medicines.