What Causes Pain Below The Shoulder Blades Radiating To Breasts?

I m having pain under my shoulder blades which goes around to the side of my breast. I have pain in my left breast which at times feels like a burning sensation. My left shoulder hurts and left arm feels numb and heavy sometimes. I ve had these symptoms for a couple of weeks. I have a mammogram and ultra sound scheduled for next week. I had my gall bladder removed years ago. What do you think this could be? Looking forward to your response. Thank you, YYYY@YYYY