What is the cause of intense pain between shoulder blades?

Muscle strain: Most likely due to strain of the muscles than bring the shouder blade together(serratus muscles)if the pain is in the middle of the back the ethiology is different.Try doing shoulder streches(so called sleepers streches)google it.It will show how to do them)use local oitment to increase heat to the affected muscles(bengay, ice-colheat).