've been experiencing a back pain on my upper left side which doesn't bother me a lot but it's there whenever I try to feel it. It's between my shoulder blade and spine. I've also been experiencing a minor chest discomfort. No pain. But I just feel... 'weird' on the left side of my chest. Note: I have a back pain similar to the current one on my left side. Same type of pain and same location between shoulderblade and spine on left side. What could this be. Please help, thanks.