I also have chronic pain (fibromyalgia) and have had a similar experience with cannabis. It makes me feel spacey and like I'm dreaming rather than awake. It didn't really reduce my pain at all, only my ability to concentrate on things that aren't pain as a distraction from the pain. Overall it left me in a worse place than before I had taken it.

I've never taken opiates for pain, only occasionally for cough (tussin + codeine during a bout of pnuemonia and again when I had bronchitis, and low dose vicodin once for about a week one winter when my asthma was extremely bad and I couldn't sleep because of the coughing).