What Causes Pain In Shoulder Blade,chest And While Breathing?

i have pain between my shoulder blades, across my chest, it is spreading and taking a deep breath puts me at a 10 on the pain scale.If I lean forward i can breathe a little easier. I ve had this all day and been to the doctor. High BP, normal bloodwork, normal EKG, chest xray clear. I have a CT scan tomorrow. It s getting worse. What could it be?