For the sprouting of any seed, water is necessary. Similarly for the sprouting of this knowledge 'I am', water and food are necessary. In the essence of the food the quality of 'I amness' is in a dormant state. As salt is in seawater, similarly, in the body, in combination with the vital breath, the consciousness appears. it is the consciousness that feels pain or pleasure not the body or the vital breath. Once you know that you are not the body, all the concepts about pain and pleasure will disappear by themselves.