What people don't get (as I am getting down voted) is that opioids simply activate the opioid receptors in the brain. When these receptors are activated they release endorphines. Endorphines are your natural pain reliever, but will also causes euphoria when no pain is present. The mount of the opioid you take corresponds to the amount of endorphins released. When you are not in enough pain to use up the amount of opioids you've taken the side effect is euphoria; whether it would be from not being in enough pain, or from taking too high a dose. Therefore, since you have never experienced a high, you are in fact suffering from pain and are taking the correct dose and therefore will not feel euphoria and will, thankfully, not understand how it becomes addicting.