Why use cannabinoids for chronic pain?
Phytocannabinoids, as we all know, have been used for therapeutic purposes throughout history, especially for their analgesic potential.
However, the circuit we are talking about is relatively young if we consider that the first official study started 20 years ago thanks to the pioneer Raphael Machoulam, whose discoveries will bring chemical elements to a pharmacological level. 
Since cannabinoid receptors were discovered, pain regulation has immediately come to the fore in studies and research.
Important evidence has shown that cannabinoids drastically reduce thermal and mechanical allodynia, proving the important role they play in the treatment of neuropathies 
Allodynia: painful impulse felt by the person following a harmless stimulus (it often happens that simply touching the affected part causes a sensation of pain).
CB1 receptors and their power against pain
These receptors represent the main mediators of the antinociceptive effect, and are distributed in the main nucleus of the brain that regulates pain (Periaqueductal gray-substantia gelatinosa-medulla oblongata-dorsal horn) 
CB1 antagonists (all substances that activate these receptors, such as TCH) prevent the phenomenon of twisting of the dorsal horn.
Hyperalgesia: increased pain sensation, usually caused by damage to pain receptors and nerve endings.
It is therefore crucial to emphasize that manipulating the cannabinoid circuit is more advantageous than using opioids for the treatment of pain-related neuropathies. [3,4]
In addition, the elements that activate the CB1 receptors maintain their effectiveness over time, unlike morphine which increasingly requires a higher dose, giving rise to an increase in side effects.
Cannabinoids vs Opioids
Pain treatments today are still, for the vast majority, opioid-based, but approximately 50% of patients find relief through available opioid-based treatments. Part of this great revolution in knowledge and man's way of life is also this: illuminating medicine, orienting it towards the use of cannabinoids for the treatment of pain. 
Below, a table that will make your ideas clearer, kindly provided to us by ALPHA CAT Company, which provides me with the kits for cannabinoid tests for inflorescences and extracts. (Zoom in a little with the screen to get clearer data)
Enjoy the reading.
British Medical Association (1997) Therapeutic Uses of Cannabis. London, Harwood Academic Publishers
Fox, A., Kesingland, A., Gentrym C., McNair, K., Patel, S., Urban, L., James, I. (2001) The role of central and peripheral Cannabinoid 1 receptors in the antihyperalgesic activity of cannabinoids in a model of neuropathic pain. Pain, 92, 91-100.
Martin, B.R., Lichtman, A.H. (1998) Cannabinoid transmission and pain perception. Neurobiol.Dis., 5, 447-461.
Lichtman, A.H., Martin, B.R. (1991) Spinal and supraspinal components of cannabinoid-induced antinociception. J.Pharmacol. Exp. Ther., 258, 517-523.
Mao, J., Price, D.D., Lu, J., Keniston, L., Mayer, D.J. (2000) Two distinctive antinociceptive systems in rats with pathological pain. Neurosci. Lett., 280, 13-16.