Can psychosomatic reactions be completely unconcious? I had always considered that psychosomatic reactions, such as Psychogenic pain, while "real" to the person experiencing them, would be a concious reaction at some level.  That is to say, if the person told themselves "this isn't real" - they would be able to tell that the reaction was "in their head". 

However, after some recent research on Couvade Syndrome I became curious if a person could have completely unconscious physchosomatic reactions that they could not suppress with "will".  Assume in this case we're talking about an otherwise mentally healthy individual who isn't hearing voices or anything like that.
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.