Yes, my pain was in my shoulder, and it could excruciating. That's a very common location. Still, my surgeon said that just when he thinks he's heard every possible post-op symptom or pain, someone comes in with a different one.
Here is a quote from a doc responding to a question about post-Nissen back pain:
"As has been commented below, back pain is fairly common after abdominal surgery. Causes can include irritated nerves referring pain to the back, to the healing process exacerbating the back pain."
He also told the person asking the question that the pain should be discussed with their surgeon, who will determine whether or not further testing is necessary.
A big issue for you right now is the bloating. I know that is incredibly uncomfortable, and I would think that it would definitely create more pain and pressure on the wrap, and even the nerves of the diaphram/stitches.
Have you called your surgeon's office regarding the bloating, and what you should expect as far as relief?
You say it hurts when you walk "too much". I do think it's worth walking less than too much...as much as you can tolerate without hurting.
Also...sometimes you can get a rib out of place or stretched muscle when they move you from the operating table to the gurney. You're dead weight, and you could have had something happen then. It's more likely to be nerve-related, but who knows?
I think you should ask your surgeon's office for some guidance with this. While the first few weeks (especially the first two) can be very uncomfortable, it sounds as if you're experiencing a higher than average amount of pain and discomfort.
I'm sure you're looking forward to the day when this part of the recovery is far behind you. Sorry I can't help more!