Glad to hear you're doing well after surgery! I had the surgery done in February 2009, and am very glad I did. The symptom that sent me to surgery was GERD related asthma that was totally out of control. Since the surgery (after time went by and the lungs healed) my lungs have been SO SO SO much improved.
As far as eating after surgery...After five days, I was eating solid foods--"anything that could be chewed to a liquid." Attending to that advice, I ate pretty much anything I wanted, and had only very mild issues with swallowing (in particular, for example, I was at a restaurant and ate a cherry tomato, which I didn't chew completely. It wasn't a big deal, but did cause some spasming and discomfort).
The shoulder pain was most likely made worse by the floating gas that travels internally after the surgery. I was one that walking really helped. My pain control was in exact relation to the amount I walked. Glad to hear you found out what's going on there.
It'll take a few months for things to get more normal for you, but being able to eat whatever you like (within reason) is a real treat. Remember to take small bites, and chew, chew, chew.
My surgeon asked me to stay away from bread and steak for a while. I found that toasted bread was fine. Also, if you enjoy beef and have a crock pot, you can combine carrots, a little onion, some potatoes, (onion soup mix with a little water) and beef. Cook it for hours, until the meat is really soft, and enjoy. A friend who'd had the surgery suggested that I do that, then just eat the veggies that were flavored with the beef, but I could eat it all.
Remember to eat SMALL meals more often, since your stomach will continue to feel full after a little food. You don't want to get uncomfortably stuffed.
When you're eating, don't talk. It causes you to swallow more air with your food, and creates more gas issues. If your stomach can burp itself, Gas-X can be a help. It won't help with the gas that's floating in your body, obviously.
I was warned by members here to get anti nausea drugs to have on hand in case of nausea. I got Zofran (little tiny pills that melt in your mouth) and Compazine suppositories from my family doc. I got a stomach virus in January that came on suddenly and didn't have nausea to warn to take the meds until it was too late. I was surprised to find that I could vomit. I took anti nausea drugs immediately, but after 4 hours threw up again. I took a dose of Compazine, and didn't throw up again, as I took it regularly to stay ahead of the nausea.
At your stage in the game you don't want to test your wrap, so be sure to get anti nausea drugs and carry them with you wherever you go. Don't be overly worried, though. Many either throw up or have dry heaves without any damage to their wrap. It's just better to take precautions if you can.
Later, when you're eating more normally, you'll want to have BEANO. You take that just before your first bite of potentially gassy food. I find it helps a LOT!
Good luck with your future healing. Feel free to ask any question that you might have. Keep in mind that my surgeon said pretty much anything can happen (symptom-wise) during (especially the early) healing process.