Figuring out the root of your health problems?

So one of the things we hear the most is ''You have to figure out what is the root of your health problems'' I.E. candida/leaky gut/Ileocecal valve problems are more like a symptom. Have heard this from a number of people who went on to live a healthy life. Wondering what some of you have done to diagnose/test your 'cause of candida'. Did you get your liver or kidneys tested? Test for food allergies ? Have always had a problem with fatigue, depression, brain fog and draining hangovers just about my whole life. Liver? I don't know. Am treating candida but don't want it coming back. Googling is a rabbit hole. Thoughts...experiences?
Thanks, appriciate the input Tweet