Answer by  
                                                                                          mamahosek (57)
                                                            
                          
                          
                                                           The most common reason for back spasms are over-pulled or sprained muscles, Also sitting or standing for long periods of time can cause cramping along with spasms. Bad posture can be a culprit as well as dehydration, injury, or arthritis. If your core lower back muscles can not support your back, this can also be a cause.