I'm sorry you're having these issues after the Nissen redo. I had my Nissen fundoplication surgery back in 2018. Fortunately, I have not had any problems like yours except for the light stinging sensation on my left side around my sternum. I have noticed I am burping a little as well. Both of the symptoms are recent occurences. I have considered making an appointment with the gastroenterologist that did the surgery to see if all is well. I hope you can get peace of mind, which always comforts me, knowing that all is well and there are no complications!