What Causes Pain And Bruising Between The Shoulder Blades?

Hi, may I answer your health queries right now ? Please type your query here.. For the past 4 or 5 days my right arm has been hurting and feeling bruised. Also my shoulder and between my shoulder blade. I haven't been to the dr. yet. I have been placing cold and warm packs on the area and taking over the counter pain medicine. Any thoughts on what it could be?