Here is a fun exercise to help you practice your body language reading skills. Turn on a movie or tv show, but turn the sound off. It is amazing when there are no words to distract us, how much better we can read the body language and understand the feelings and emotions of the communication.
Feeling back stiffness may be all in the head, not in the back
Feelings of back stiffness may be a subjective protective construct of the mind, rather than reflecting objective biomechanical properties of the back.