Hi Thank you for your question to HCM. Pain in the lower back on either side can come from multiple reasons that lead to paraspinal muscle spasm or from inner organs. Pain related to kidneys is usually felt in the subcostal angle which is just below the rib cage and on one side of the midline in back. A tenderness elicited by pressing deep in this region would indicate kidneys as a likely cause. In your case it would be helpful to know your age, how long the pain has been there, was there any inciting event that started this pain and are there any related symptoms like fever or any urinary symptoms. I would recommend if the pain persists for a long time or symptoms worsen, you will need to see a doctor to find out the cause of your pain. Hope this is helpful. I would be happy to answer any questions you may have.