Answer by  
                                                                                          IanGlassford (27)
                                                            
                          
                          
                                                           Most muscle tightness is caused by two things, either that resulting from exercise or from an injury, such as a pulled muscle. Muscle tightness from exercise, such as running or weightlifting, can be alleviated by simple stretches that can be performed before or after exercise on a routine basis. Not stretching can eventually result in serious injury.