Mazahuh,
Can you send an email or make a phone call to your doctor (cardiologist or surgeon) to report the pain in your arm(s)? Also, in my opinion as a side sleeper who get pain in my arms sometimes, in the position they likely had to place you during surgery, it may be that you sustained a pinched nerve in either your shoulder or neck, which is sending new messages to your arm area. But in order to put your mind at ease, see if you can talk to someone in your doctor's office.
Was your surgery on an emergency basis? Or had the surgery been discussed previously?
Keep us updated. Best Wishes on your recovery