How can I get access to affordable US Health care as an American who lives in France?

It has been almost 2 years and I really feel like there is something not right with my health but the doctors in France aren't listening. I have swollen lymph nodes for over a year now. Some disappear, then reappear in different locations. And I am very fatigued and have itching behind my knees at night that wakes me up. Yet there is not a rash nor insect bite. It seems like the doctors in France rely strictly on "complete blood counts" for everything and if your blood tests are normal, then there is nothing wrong with you. I wonder if it would be the same in the US system, considering France was the winner of the WHO's "Best Medical System in the World" award. Shoudl I purchase an insurance plan on the web and seek treatment in the US?