Pain is important for our life because it is a signal of danger. Continuous pain is not good for our body because is not useful for our survival and it’s a torment. 76 milions of Americans out of American citizens, that is a persentatge is a 28%, suffer pain. (inflammation, cancer, diseases, diabetes…)
In a experiment with humans we use a heat stimuli (laser) and we make a brain seammer if the human think about plesant things they suffer less pain ( yellow areas in the brain).

A chinese plant was discovered recently against pain in a clinical trial in the US is a root extract of thunder god vine.