I have severe sharp pain that seems to start from the left shoulder blade and has moved down my left arm to my hand and now is radiating across my che?

Many possibilities . First and foremost see your doctor to make sure you are not having a heart related problem. There are many other causes for this type of pain as well such as a pinched nerve..C6 or c7 for example. Please see your doctor to establish a firm diagnosis and make sure it isn't cardiac related right away.