Chronic pain service don't try to 'get you off' drugs exactly, they can try to teach you coping techniques in order for you to minimise your dosage as much as possible while maximising quality of life and activity. Unfortunately, there is not a one-size fits all solution with chronic pain, which is why many GPs resort to opioid scripts.

Long-term opioid usage is bad for you, however, you are correct. I can't remember the exact timeframe, but opiate usage is supposed to be regarded as 'long-term' around one month. So taking an opioid for years is obviously not a grand solution, but frequently the only one available in order to function as a human being for chronic pain sufferers. Combined with the tolerance factor, things can start to get fairly messy rather quickly - in fact, the increasing usage of heroin in the US, with the typical user now being a white female in her 20s is linked to long-term usage of opiates.

There are numerous other issues with long-term opiate usage causing chemical changes in the body and brain, such as the reduction in testosterone levels - particularly scary is the possibility for testicular atrophy, and equivalent damage to a woman's ovaries leading to sterilisation.

The unfortunate fact is that there is, effectively, no painkiller available that is suitable for chronic pain. Despite the potentially horrendous side effects, opioids are the only solution that is available for many chronic pain sufferers - pain management techniques can only go so far. There's loads of other things I could mention but I think that's enough for now.

source: Been on opioids since 14, going through codeine, buprenorphine, tramadol, etc. Happily, the worst side effect I have suffered gave me my username.