I was banded on 7/13, and I also had a hiatal hernia that was repaired. I experienced pains from shoulder to shoulder and found it hard to breath. Like most people said, it was from the gas. This lasted for only a few days and my pain meds helped me sleep, which in turn helped me not feel the pain. I am 9 days post surgery and don't have any chest pain. I only have slight incision pain.
Some Dr.'s perform a test prior to the surgery to determine if their is a hernia, others repair it if it is spotted during surgey. I'm glad that it was caught and repaired because I already experienced heartburn and acid reflux, and I didn't want it to be any worse with the band.
Good Luck!