Most of the back spasms affect the lower area of the back which can be due to lifting something heavy, waking up suddenly or getting out of the bed or a sudden jerky movement. Other factors that cause back spasms are obesity, structural imbalance in the body, dehydration, electrolyte loss, poor sleeping positions and maintaining a poor posture. For best results go see a doctor but in the mean time, here are some home remedies for instant relief.