Last Updated: 3/15/2019, Marc Woodard Scientific studies prove, pain relief decreases while pain sensitivity increases from excess use of opioids. In other words, if you’re a chronic pain sufferer and have used opioids for long periods of time, greater sensitivity to pain will occur. So you ask yourself, how could taking more pain killers cause greater sensitivity to pain? “I thought pain killers were supposed to lessen the pain.” This is true if you are following the