Is there something wrong with the cervical spine when the neck leans forward? If it may be because of habitual sitting upright, the cervical spine will bend forward. Well, I think you should stand against the wall at ordinary times, for example, and then lean your head back. Stand for a few minutes first, and then the time will lengthen bit by bit, so that you can, uh, stand up straight. In that case, I think you will form this good habit after a long time.