What causes short muscular chest pain above the breasts? this happens to me once in a while.

Heavy lifting/weight: Sounds like you were diagnosed with a pectoralis muscle strain ("muscular chest pain above breasts"). It is common in weightlifters & athletes who use their hands a lot. The pec muscle moves the arms forward (fly press) - excess weight in deconditioned athletes will cause it to spasm, even longer after you're done w/ weights. Best to rest, use heat to relax muscle, & TTYD about medications, if any