Can anyone tell me the difference???

My boyfriend has been complaining of chest pain. Nothing to horrible, but it seems that when he does any lifting, any sitting or standing for too long he has sharp pains in the left middle of his pecktorial. I don't know if it is of any concern but its starting to effect his performance in working envornments. He is getting really frustrated because if he lifts anything over 20 LBS or gets really stressed the pain comes back.
He went to the ER about 2 years ago and they told him that it was costo... something that I cant pronounce or even type. It is when a piece of muscle in the chest area becomes torn loose and sways, it says that it is usually healed in a matter of months but this sharp pain has lasted years... more frequent now more than ever.
Does anyone know the diffrence between a torn muscle that just wont heal or something to be really concerned about???

           Thank you,
                 Torri
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