It happens because you are sensitive to the difference between the notes of music and can feel their effects in the very body. Music and speech have a heavy impact upon us including the functioning of the body but one has to be developed enough to sense it. The kind of music you mention generally stimulates the lower vital regions and the organs involved, thereby creating a lowering of consciousness and an imbalance which you experience as headache. While one has to grow in strength and equanimity towards everything, one has also learn to discern between the high and the low, the true and the false. It is a good sign that you are able to sense the difference instinctively.
Affectionately,
Alok Da
