Life expectancy/chronic pain
Your question is very valid.
If you have pathology causing pain- infection, lesions, etc., you are at greater risk. One of the insidious features of pain, however, is hypertension and changes in your HPA- your adrenal-corticoid-hypothalamic complex. Over time, the body can thro too much adrenaline, cortisol, hormones, etc. It can also interfere with your kidney-heart complex that regulates BP. The best thing you can do is have frequest checkups, try to exercise as much as you can, eat a healthy diet, and use techniques to lower sterss- hence BP, like Tai Chi, that won't cause excess pain, but will help keep you well.
Also, keep track of your psychology- find joy where you can or all is gray- keep your mind active.
God bless and god luck.