I'm limiting my question to this field because it is the only one I know of with a certain degree of knowledge.
I doubt they really exist because of the following reasoning:
Coulombs law was stated because it makes mathematical sense (think of "force directly proportional to the charges and inversely proportional to the radius squared"). Then, someone created this mathematical field be dividing by the force by the test charge and said the electric field is kq/r^2. But I see this only as a mathematical tool, I just can't see how why it is a fact that the electric field exists.
Is there any proof that it exists? I can only think of proving it after measuring a force caused by it, but I don't think that would be proving the electric field exists.
What bothers me most is this jargon of "energy stored in the field". I just can't believe energy is stored in the field, it seems way too magical for me. The way I'm thinking of "energy stored in a field" is as if it were some type of hypothetical case. Like "how much would be released if all the charges creating the field in the system released all their potential energy".
I hope someone can demystify this for me.
Edit: I can see this question might seem like philosophical babble. But it really is not!