There are many causes of vague pain under the right back. The common causes of vague pain under the right back are as follows: First, it may be due to long-term strain or over-exercise and lack of good rest leading to lumbar muscle strain, and the symptoms of vague pain under the right back will appear. This can be treated by acupuncture, massage therapy, infrared irradiation therapy and ultrashort wave therapy to unblock the back meridians and blood and improve the symptoms of back muscle stiffness so as to reduce and eliminate the pain. Secondly, it may also be caused by internal tumors, such as lung tumors or liver tumors. If it is caused by tumors, in addition to pain, it is usually accompanied by unexplained weight loss and mental fatigue, which must be further diagnosed by blood sampling and radiographic examination in hospitals, and then choose whether to undergo radiotherapy, chemotherapy or surgery according to the examination results.