Girls, hi! I'm bothered by pain in my back in the area (on the photo)…

Girls, hi! I'm bothered by pain in my back in the area (on the photo). It's a dull ache in the evening and at night. In the morning I wake up without any pain, and it starts every evening. I thought it depends on how the day went. Even if I lie down all day or walk all day, the same song plays. The bandage doesn't help or I wear it wrong... Weight gain of 10 kg. Could this be the reason?