Pain and our right to pursue happiness

The declaration of Independence states that we have an inalienable right to life liberty and the pursuit of happiness. Why then is the government prohibiting doctors of chronic pain patients, especially those who have no shown no signs of abuse, from prescribing necessary pain medications to their patients especially those who suffers from pain every day. I contend that it is absolutely impossible for someone who suffers from chronic pain as a result of multiple conditions to be adequately treated so that they can pursue happiness. Therefore I am convinced that this is a violation of what our founding fathers said was a right that could not be denied.