Good question and this is very big topic mate. Short answer is - every psychosomatic disorder is unconscious in the sense that it's coming from psychological tension but reflects itself in some unpleasant somatic/bodily reaction (e.g. headache, lower back pain, high blood pressure). In general, even if you are conscious of the source of psychosomatic reaction (e.g. stressful job causing evening headaches) you can't really talk yourself out of it. But you still can make some short term changes (pop a pill) or long term changes that (quit a job, meditate) to reduce the psychosomatic effects (Grossman et al., 2004).
Grossman, P., Niemann, L., Schmidt, S., Walach, H. (2004)
Mindfulness-based stress reduction and health benefits - A
meta-analysis. JOURNAL OF PSYCHOSOMATIC RESEARCH, 57 (1): 35-43
But it's probably not that simple. While we can say that psychosomatic disorders are by default unconscious, we need to consider wider range of factors that causes them and ask more questions.
One such question is why people get psychosomatic disorders? Stress is the best, most popular, most studied, most quoted, and most mysterious, simple, single answer to this question. Ulcers, asthma, chronic fatigue syndrome, rheumatoid arthritis - you name it. In general terms, increase in cortisol due to stress punches holes in your body, although the lack of cortisol has been argued to have impact too (Heim et al. 2000).
Heim, C., Ehlert, U., Hellhammer, DH., (2000) The potential role of
hypocortisolism in the pathophysiology of stress-related bodily
disorders. PSYCHONEUROENDOCRINOLOGY, 25 (1): 1-35.
But you see, the longer I think about it, the more complicated it becomes. So I stop here.