The purpose of the study is to investigate whether Gua sha is an effective modality for relieving chronic low back pain specifically in the aged population by comparing the baseline measures of pain intensity, self-perceived disability, back range of motion, back local muscle stiffness, depression, sleeping quality, quality of life, biomarkers measurement, and analgesic intake on days 1 and 7 after a single session of Gua sha treatment. In addition, the investigators are going to compare between Gua sha and hot pack treatments for the above parameters.