This is information only. I have suffered from chronic nausea that only, but not always, relieved by lying down for the past 8 YEARS. Other than that I am in a perpetual state of what feels like motion sickness/car sickness. It makes it hard to do anything.
Recently I was referred by friend to a cardiology clinic, sub-clinic called "Faint and Fall Clinic." (The clinic was set up for people who have unexplained dizziness, unexplained nausea and unexplained fainting.) I went and during the initial visit the cardiologist told me not to take in any caffeine or chocolate, and the salt my food as much as I could tolerate. Also advised me to drink at least 90 ounces of water a day. I did that for a month with no change in the chronic nausea. Last Friday I underwent a tilt table test which confirmed that I have issues, which when bundled together, is called dysautonomia (dysfunction of the autonomic nervous system). The doctor is not sure why or what type, as there are many. Simply put, my autonomic nervous system is not working properly and keeping me not only nauseaous but also with bladder issues, chronic insomnia, panic feeling, fine tremors, double vision and blurred vision for the past three years, and the list goes on and on.
If you are experiencing a cluster of symptoms and don't have any diagnosis, or even if you have a diagnosis and it doesn't seem to fit all of your symptoms, please Google "dysautonomia" and look at the symptoms.
I was diagnosed with Sjogren's many years ago and I now believe its related to the dysautonomia.
This discussion is related to Long-term nausea/vomiting: symptoms only subside if I lay down