I have a pain under my right shoulder blade, there is a sharp pain every time i move my right arm, i was just wondering what might cause this? do i need to see a doctor?

Possibly: Sudden pain in shoulder blade in a young make like yourself can sometimes be due to a spontaneous pneumothorax - a small area of collapsed lung. Usually this resolved on its own but if you have pain with breathing or shortness of breath it would be best to see Dr & possibly have a chest X-ray to evaluate. If none of those symptoms you can try ibuprofen or Aleve & heat & gentle stretches 1st