assumed that somehow both FM & CFS go together, is it true?
They don't "go together". They CAN be found in the same person, but they do not always occur in the same person. They are separate syndromes, with some overlap in their manifestation and symptoms. Most people have either one or the other.
Fibromyalgia can cause extreme fatigue, so sometimes people with fibro think they have ME/CFS. And some people with ME experience chronic pain. Basically, if the main thing you experience is pain (with fatigue accompanying it) then you more likely have fibro. If your #1 problem is severe fatigue chronically, to the point that you really can't get much of anything done and the pain is a lesser symptom, then you'd be more likely to be diagnosed with ME.
But neither one is just diagnosed by their symptoms.
All of the other tests have to be done to eliminate the other diseases and syndromes that could cause the symptoms.
Edema that I now read is part of Fibromyalgia, is this true?
Fibromyalgia doesn't cause edema. That is probably being caused by something else. One main cause of edema is lack of physical activity. Staying in bed a lot will exacerbate this. There are other causes as well, such as diet, and you can look up the causes on the internet.
I don’t believe the results of my tests because I feels like all I’ve been through, emotionally & physically, what I inherited & just aging must have effected my heart, or liver, or kidneys in someway or somehow.
I understand where you are coming from on this, but your feeling that it "must" have affected your internal organs "some way, somehow" doesn't mean that it has. I suggest that you take the word of the doctors on this rather than refusing to believe there's nothing wrong with those organs. It is much healthier for you, as well as being more realistic, to accept the results of the tests. Those tests do not lie.
Personally I feel that I am going to have/or may have Congestive Heart Failure like my Grandma. All signs of edema is leading me in that direction.
This may happen to you or may not. I always think it's best not to "borrow trouble" by assuming something bad will happen when there's no way to predict the future. Thinking negatively about the future or about what will happen to you can't help you. And there is some evidence to suggest that if you insist on believing that some specific thing will go wrong with your body it can actually cause that thing to happen when it otherwise would not have. The mind is a powerful thing; best to use it for positive rather than negative.
Because ME/CFS & COVID have the same symtoms .
Ummm....no. Covid is a virus that causes serious upper respiratory problems and flu-like symptoms. Chronic fatigue or ME does not have those symptoms. ME is characterized by fatigue, not by upper respiratory symptoms.
The only thing that ME/CFS has in common with covid is fatigue, but fatigue is generally associated with any illness; even having a cold will make you tired because your body is using energy to fight off the illness..
I am glad you can live with family and that they help you. You are very fortunate in that, even though not in other ways. You are certainly welcome here and I hope the forum will be helpful to you.