Ex drug worker here. Well done for taking the first steps to changing your addiction! You’ve had lots of great advice on this thread. Recovery looks different for everyone - some people really benefit from working with a drug worker, or a 12 step programme, or with an opiate replacement programme, and some do it completely alone. There are lots of tools out there which could help. There isn’t a correct way - it’s whatever works for you. If you try something and it doesn’t work, don’t be discouraged. Take time to reflect, be kind to yourself and keep going.
Some people benefit from understanding theories of addiction.
Have you heard of the change model of addiction? It can help to see where you are in this cycle and realise that what you’re feeling is completely normal. Have a look at this link and see if you can recognise yourself: www.smartrecovery.org/smart-articles/the-stages-of-change/
It sounds like you might be “contemplating” change... to give yourself a boost into the next stage it can be really helpful to do a cost benefit analysis. Get a piece of paper and make some lists. Do it in the following order...
The benefits of using codeine (eg it manages your pain)
The costs of using codeine (eg you have to spend a lot of time sourcing it)
The costs of stopping using codeine (eg it will be scary and tough)
The benefits of stopping using codeine (eg you will be free of your addiction)
The more detail you can go into, especially on the last section, the more you can persuade yourself to take action.
This is part of a motivational interview technique. You could look that up and see if it would be helpful. Also have a look at the SMART website above. They use CBT based tools to support recovery.
Also consider contacting your local drug service. They may be able to offer 1:1 time with you and/or provide online tools which you can work through at your own pace. Good luck. You’ve already given up alcohol which is equally, if not more, physically addictive than codeine so you can definitely give up codeine too.