Why is every problem taken to have a physical cause?

I read many a link, and I am totally puzzled as to why I often see assumptions that every problem (many assumed to be imaginary, like Scrooge's undigested bit of beef) has a physical root, and can be cured by doctors, nutritionists, exercise, vitamins. Emotional problems are not assumed to have any connection with circumstances, save that one who is kicked down the stairs and feels hurt should recognise this as an imagined slight and get rid of it with Prozac. One who has marital problems just needs some endorphins, which pumping a bit of iron shall supply.

For the record, I believe it is important for those physically or mentally ill to obtain the proper medical treatment. I am in no way denying that illness of the body can affect the mind as well. My complaint is that thinking tofu, aerobics, or doctors are the cure for all ills.

Perhaps it gives people a sense of control. Many problems have no solution available - others are too painful for us to face. Or trusting all to some latter day magician, who takes one under total control whilst convincing one that all the problems lie in these herbs or in not eating meat, gives a sense of security. All I have seen it lead to is self absorption, misunderstanding of true illness, and a sad tendency to ignore what might be essential spiritual problems or difficulties in relationships.

What if, for example, deep down we know we are wronging others? Isn't facing this much healthier than reading self help books which will convince us they 'chose' to be harmed, or thinking we can eliminate the problem with a run?