Sudden back pain can have many causes. One of the most common is lifting an object that is too heavy or lifting incorrectly. This will often cause pain right away. In other cases, an acute back injury can be suffered after a motor vehicle accident. The force of the crash can put enormous stress on your back, leading to strains or even muscle tears in the back. Bending, reaching, or twisting can also lead to acute back injuries that cause significant pain.
Severe back pain can be caused by conditions that put stress and pressure on nerve roots, such as herniated discs and spinal stenosis. Although rare, acute back pain can occur as a result of spinal tumors that grow on the spinal cord or on nerve endings or due to bacterial infections.