Is it possible that qigong can hurt the body when the person is trying it out and did something wrong? can anything go wrong while the person is doing qigong? is qi harmful in the same way as it is helpful?

There are many factors that can affect the relative safety of a ch'i kung practise. Healthy ch'i kung is meant to balance the energy distributed throughout the body. If that distribution proceeds out of balance - either through inexperience, incompetent instruction, restlessness or greed, then the balance of the distribution can go awry. Some of these energies are powerful, and can either chronically overheat or starve various parts of the body of the energy necessary to their function if misdirected. Therefore, it is vitally important to have a qualified instructor, otherwise there is absolutely no way to avoid either mental or physical health problems from unbalanced practise down the road.