My 22 Year Old Grandson Had Soreness In His Right

My 22 year old grandson had soreness in his right shoulder area yesterday he works out and afterwards we noticed one side of his chest was flat while the other side was built up. Today his shoulder feels fine and his chest is equal to the other side. But, he now has a fluid pocket above his belly button, it’s very soft and mushy, it goes to his left side with a darkish line under the sack. Is this something he should worry about and go to the ER or it can wait for a Doctors appoint.