To work efficiently, your muscles and joints need a steady supply of oxygen-rich blood. Smoking not only tightens arteries, but it decreases the rate at which oxygen and carbon dioxide are exchanged in the blood. In other words, when you smoke your muscles not only get less blood, but lower quality blood.
Other side effects of smoking include fatigue, chronic lung disorders and a slowed ability for the body to heal itself, which indirectly affect chronic pain. Fatigue and lung disorders lead to inactivity, which causes deconditioning. Slowed healing means that injuries affect you for longer than usual, and healing from surgeries or infections can be problematic.
Giving up smoking is not easy, but it can help you get part of your life back from chronic pain.
Sources:
The Pain Clinic. “Stop Smoking.” Accessed January 22, 2009.
Jamison et al. “The Relationship Between Cigarette Smoking and Chronic Low Back Pain.” Addictive Behaviors. 1991;16(3-4):103-10.


