What Causes Recurring Pain In Chest And Shoulder Blades?

im a receiving manager at a retail store so my work is very physical i have recurring pains in my chest and shoulder blades it comes and goes but this time i can hardly move or sleep every movement is wretching and like getting out of bed is the worst the pain seems almost unbearable im sure i pulled something but muscle relexers, painkillers, and muscle rub does nothing to help does this sound like i pulled something?