This few weeks, i feel that my back became warm though i'm in a cold place. what does it mean? is there something wrong of my back?

Probably fine: It is unclear if you mean that you have a warm sensation or if you notice heat when you feel your back. Assuming the latter, it is normal to notice that your core, or trunk, is the warmest part of your body even if you are in a cold place. Your vital organs are inside the abdomen and chest, so your body keeps you warmest there. Some clothes that don't breathe well such as polyester cause warmth