There's no way to know if one has a psychosomatic illness or not unless one goes to the doctors and has tests done to rule out any known physical causes. Psychosomatic problems are real illnesses, real things go wrong but the cause is thought to be stress. People get stress headaches, for example. The headache is real but doesn't necessarily go away with a pill (or won't stay away/heal) because that doesn't relieve the stress. Psychosomatic isn't something imaginary, it's very real but caused by emotional stress or damaging thought patterns. But all other reasons have to be ruled out first. You may not know if you're having a heart attack or a panic attack for the first time, for example, without the trip to the ER that says it's a panic attack.