What meds are you on,some side effects is coughing.
I have had numerous lung tests and all are normal. All my heart functions are normal. I have been evaluated in depth at 2 teaching hospitals (Duke and UNC) and all the docs I've seen are puzzled. My current doctor is recommending alternative treatment (acupuncture, bio-feedback, etc) as traditional medicine is not working. Both surgeons that performed the fundos told me before the surgery that there was a 10% chance the Fundoplication would not help the coughing.
If I had a coughing problem, like you have described, I would get myself a referral to a Pulmonoligist. If the Vagus nerve or CHF or GERD are the reasons, he is the Specialist that can answer that.
You might need a lung-function test and possibly xray?
I'm not a health professional, so this is just a thought from a person who had a cough prior to my fundoplication...
There are lots of reasons for coughing, including congestive heart failure, GERD, COPD, obesity, and there is also the chance that the Vegas Nerve can be cut during the surgery. It sounds like you need to have the reasons for your coughing sorted out carefully. Hopefully you are insured, I'd ask for a second opinion from the nearest teaching hospital where you live. If you are aren't getting better, I'd ask for a different look from different doctors.
keep us informed and best wishes.