Sharp lower back pain can be caused by so many different conditions it is difficult to really get a fix on what the cause could be. All you really know for sure is you have sharp lower back pain and it is sudden, persistent and usually below the waist. Although this is no consolation, this is a very common occurrence for the majority of the population.

If push came to shove, the most common guess on why you are suffering from sharp lower back pain would be muscle strain as a result of heavy physical work or lifting, bending or twisting the wrong way, or sitting or standing in really weird positions (anyone ever try and paint a ceiling overhand over your head?). On their own these movements can cause sharp lower back pain, but they may also aggravate existing sharp lower back pain.
Other possibilities for sharp lower back pain can and do include spinal stenosis (when channels in the spine containing the spinal cord and nerve roots become restricted), arthritis, spinal infection, tumors, a condition called spondylolisthesis (when one of the spine’s bones slips forward over the vertebra beneath it) and fractures. Now we’re certain that since you are reading this, you are likely hoping the cause of your sharp lower back pain is NOT one of the above.
Categories of sharp lower back pain fall into either the acute or chronic areas. Acute may come on out of nowhere like a freight train and bring intense pain that usually (but not always) lasts less than three months. Chronic, as you well know, means you have it often for your lifetime, and unfortunately, chronic pain can even have episodes of acute pain.
What would you be looking for, what signs do you need to relay to your doctor? Generally speaking when listing the signs of sharp lower back pain you would be pointing to a specific area of the lower back. It would have general aching or pain that radiates into your lower back, butt and legs. You might even have numbness, tingling or weakness. Again, generally speaking, low-level signs of problems are not cause for great concern as they can usually be dealt with speedily. If however you have bowel or bladder problems because of it and severe numbness that does not subside call your doctor.
So what would your doctor be doing to figure out why you are suffering from sharp lower back pain? Besides taking a full history, he would do something called a range of motion check. You stand straight up (as best you can while in pain that is) and how you stand is evaluated, as is how you bend forward, backward and to the sides. Anything that doesn’t look right is noted.

Next your doctor will do a slow and careful palpation of the spine that may reveal muscle spasms, displacements or other sore points. By the way, your doctor will also do an abdominal palpation to check for any organ involvement. Then get ready for a series of neurological assessments, lab tests, and imaging studies to try and get to the bottom of your back problem.