Back pain can have many different degrees of pain from constant pain to sudden sharp twinges that hinder normal movement. Pain and weakness in the specific area can even cause muscle contractures along various parts of the spine which acts as a protective mechanism guarding the body from doing further damage to the affected area. It can occur suddenly and increase in severity over time due to various factors such as a fall or improper lifting.
What are some of the causes of back pain?

An accident or recent fall, lifting or lifting weight improperly.
Muscle contractures can be caused by long durations of sitting, improper repetitive movements or bad postural habits.
The natural aging process.
Having lowered physical health and not exercising regularly.
Muscle contractures can be caused by long durations of sitting, improper repetitive movements or bad postural habits.
Scoliosis (causing one leg to be higher than the other) or pushing weight improperly.
Increased body weight, which overloads the spine causing premature degeneration.