Hi guys.. for the past few years I have had a nagging dull ache in he same spot in my upper left section of my back And it comes and goes. I notice it sometimes a lot more when I'm laying down.. and for some reason I've tied it to indigestion or acid reflux? I'm not entirely sure. My doc doesn't seem super concerned. If it was something serious I definitely would know by now right? It's been about four years that I've had this pain and it can go absent for months at a time. Has anyone else had this? Should I be nervous? What could it be?