Fentany
If you are looking for significant pain relief, Fentany or Fentanyl is a great place to start. It is a synthetic opioid analgesic that is a strong agonist when it comes to mu opioid receptors. It has been used in combinations with benzo drugs and is about 100 times more powerful than morphine. This is probably not the best choice for individuals that would like to control their pain, and also retain full clarity and cognitive abilities.
Methadone
Methadone is also a synthetic opioid which is not addictive according to most studies. It is used to help people that have opioid addictions, and works on the same opioid receptors that morphine and heroin interact with. It's great for managing chronic pain, and is relatively low in cost. If you would like to get off of opioids, this is the best drug to choose, especially if you still need to control your pain everyday when looking at opioids and morphine derivatives were even using morphine itself.
Although pain management can be very difficult to assess, especially from a doctor's point of view, they will likely do a series of tests to help determine which medication will be best for you. Hopefully one of these drugs will allow you to lead a more comfortable life, allowing you to have the clarity and pain free existence that you deserve every day.