Shallow breathing 2 years after n. fund. surgery.

Hello all:
It's been more than two years since I had open n. Fundoplication surgery. I have no regrets about the surgery. Yes it was hard but I have no more pain or gerd. I had a grade 4 paraesophageal hernia. My stomach was stuck up behind my heart and upside down! Ugh. That said, I still do not feel that I have the lung capacity that I did pre/hernia. As a scuba diver, I use to depend on lung capacity in the event of emergency. As my hernia condition worsened breathing was nearly impossible. While I certainly breathe better after surgery I have never really regained the ability to expand the abdominal area for deep breathing. Has anyone else who had this surgery noticed an inability to really expand the lungs and abdomen, even years after?