Sharp left shoulder pain. hurts more when i take a deep breath, lie down or get up. i can move my left arm with no pain. no physical signs of trauma.

Not clear: Typically if pain is related to movement it is muscle related. You need to also consider pneumonia or in your age range to consider, though unlikely, a blood clot especially if you are on birth control. Heart disease or inflammatory diseases are something to consider although less likely. See your doctor for a full exam and history.