Most back pain is not structural and does not cause long-term problems. Studies have been done to determine who needs x-rays and mri
's and who doesn't. Imaging
studies are frequently overused in what is called "defensive medicine"--an attempt to ward off lawsuits for missed diagnoses.
On the other hand, the spine is quite complex and certain conditions can be serious. Back pain with a foot drop
(weakness pulling up the toes) or loss of bowel
function can mean a serious nerve injury
. Other conditions, such as kidney stones, can cause back pain as well.
What we do know is that there is likelihood of MRI abnormalities, even without symptoms, that is proportionate to age. That is: about 30% of 30-year-olds will have some disk abnormality, 40% of 40-year-olds, etc. Just because there is an abnormality does not mean it is causing your symptoms. Over-imaging leads to surgeries which leads to complications. This is a situation where there can be definite harm in over-treating.
It sounds like you are having spasms that arch your back. They can be quite painful and difficult to break.
The safest answer, of course, is the "defensive" answer--go to a physician. However, be mindful of the possibility of being over-treated and seriously consider a second (or third) opinion. Unless there are concerning findings, such as weakness or a mass, do not rush into any treatment plan.