I’m sorry to hear Max isn’t doing well. It looks like you posted this yesterday. Were you able to take him to the vet? The first thing they are going to look for is some kind of injury to his front leg and shoulder. Only after ruling out injury would they move on to other possibilities. X-rays can reveal a lot, but not all injuries are going to involve a broken bone or fracture. There are injuries to soft tissue and ligaments, for example, that could cause similar symptoms.