Sorry I missed your post. Does your back hurt anyother time than just in the morning? What kind of symptoms do you have? I'm having difficulty in understanding exactly what is going on for you. I know my back hurts a lot in the morning, I think it is due to the arthritis I have, as I start moving around it usually loosens up some. I have had two back surgeries, but it wasn't soreness in the morning that lead to the surgeries.
The soreness from standing, sitting and laying on your stomach, also are definitive enough, for me to speculate. As far as the dip in, are you referring to the lordis of the spine? If so very normal. Let me know exactly what you are referring to with the dip in.
Good luck