Hello emma and dencha, and welcome to to the forum. I had my nissen last July, and while the recovery can be really tough (for some worse than for others), for most everyone the results were pretty good.
Dencha, is sounds like you've suffered long enough; I was diagnosed with asthma as well as a host of other pulmonary issues; the reflux turned out to be the culprit. I was constantly aspirating the acid while sleeping and while it did cause permanent damage, my lungs have been able to compensate for it and I am breathing better than I have in years. I hope that this is the case for you and that your breathing issues will become a thing of the past!
Emma, welcome to the other side! you're just new to the recovery process and you'll undoubtedly have good days and some not so good days. It's unusual to have a gastrotube for a lap nissen, so I hope everything went well; I'm surprised too that they sent you home so early. For the shoulder pain, start chewing gas-x and try some liquid motrin (childrens); this should help a great deal. If you have a good chiropractor ask her/him to do an adjustment in your ribs and shoulder are...don't know why that helps, but it does! Pay close attention to your Dr.'s orders for eating, lifting, exercising and you'll come out of this so much better!!
The younger you are when you have this, the easier it seems your recovery is (that is based on a very un-scientific survey!!), but it does seem to hold up!
Come back here for any advice, a shoulder to lean on and to definitely let us know how you're doing. (Dencha, there is nothing wrong with your post, I wouldn't worry about it).