There is no general definition of the term shaman. The ethnologists assumption that shamanism developed from archaic forms of religious rites is documented by for example, the prehistoric cave drawings in France.
The word "shaman" probably originates from the Tungusic Evenki language of North Asia, specifically for the spirit-workers in these cultures.
But it doesn't really matter where the word originates from, as one form or another has been practiced all around the world. Therefore there is no traditional or "real" shamanism. A shaman always works in his own unique way and when he dies, his very own shamanism dies with him.
The teachings of many holistic healing methods assume that through a disharmony in our lifestyle sickness is caused. By being out of tune with the natural stream of life and constantly going against the needs of our body and soul, we can develop one or multiple medical conditions.
A shamanic healer has various ways of aligning your body and soul with the natural stream of life. As everybody is unique, each healing session is specifically designed for your needs.