It should be low back pain caused by meridian obstruction. "Sleeping on a hard bed is more painful" means that your back muscles are very tight, and the muscles lose their original supporting function, leading to problems in the spine (in severe cases, physiological bending and straightening will occur). I used to have pains in all parts of the thoracic and lumbar vertebrae. When I went to the hospital to take photos, my body bent straight (slightly). I can't sleep on my back, so I need to sleep on my side, or my back will hurt badly. My suggestion is to go to the massage department of Chinese medicine hospital and let the doctor have a look. Just touch it to know if there is anything wrong with the spine, and then decide whether to take a picture. Then follow the following steps (if the result is disc herniation or dislocation, please reset in the massage department first and then massage with the fat-pushing massager, remember! Otherwise, the more you press it, the bigger the problem):

Massage your back with a fat-pushing massager (or weight-loss belt). You don't need to press it back and forth. Press one place and change it to another. It is effective to heat your skin (usually it takes two to five minutes for each place, where each place refers to all the skin on your back, not just the painful place).

At first, you may feel itchy, flushed and even wheezing, but these are normal phenomena (they will disappear after a day or two, please refer to meridians as waterways for details). Later, there may be a little red sore (the immune system is removing toxins) and skin pain in some places, and then you can massage again after the pain disappears. If you do this repeatedly, the back pain will be improved or even disappeared after three to five times.