Having pain between your shoulder blades can be caused by many things and is known as interscapular pain.
Most times pain between shoulder blades is caused by something as simple as muscle strain and if the pain in your should blades was caused by muscle strain then it should go away within a day or so.
If the pain in your shoulder blade lasts longer than a few days then it could be something more serious such as lung cancer or a heart attack.
If the pain in your shoulder blade does last longer than a few days you should really see your doctor about it just to be sure it's not something serious.