Left arm pain after heart attack

My grandfather has had ongoing heart attacks with no chest pain for the last 8 months, he is really sick in the icu right now. He is too old to operate and they say nothing can be done about his heart condition but he is extremely uncomfortable and in a lot of pain from his left shoulder and arm. He was home when out of no where he got a severe pain in his left shoulder and arm. When they did blood work it showed his heart enzymes were out of wack. The doctors dont think his arm pain is due to a heart attack because its been 4 days now and his arm is stil in severe pain. They never did xrays or an mri on his arm, only gave him morphine for pain. Just wondering how long arm pain can last from a heart attack before I push for other testing done to figure out whats wrong with his arm. He was really weak and had poor breathing before his arm pain, but now he is much worse and can barely walk.