What issues are there from long-term use of opioids for chronic pain? I've had many back surgeries & will have to take them for the foreseeable future.

Several. Not just addiction but tolerance to the pain killing effect of opiates which will result in higher doses and more side effects and hyperalgesia in which the pain actually gets worse from the chronic use of opiates.
Addiction. Addiction is one of the biggest concerns with long-term opioid usage. I would suggest that you coordinate your care with a qualified pain management doctor and team.
The problem with. Opiates are that they only "take the edge off".They can be a useful tool if you understand this. Asking them to relieve all your pain all the time is like asking my '75vw to go 90mph. Many people confuse addiction (changes in behavior to get more meds) to dependence (physical craving that can always happen to certain meds) most studies show no organ damage from opiates, although side effects exist.