Here is an article with an overview of medical marijuana for chronic pain. Lots of studies are linked to.
Here's an image from leafscience.com showing the endocannabinoid receptors that THC and CBD modulate.
In short, both the THC and CBD in medical marijuana can help folks with chronic pain live their lives better. A lot of folks would rather NOT take their opiate pain medicine, if only they could find an effective alternative. I think our NYS legislators need to hear about this, don't you?