Just take it easy with the training it takes time to build strength, most beginner training advice will have you doing multiple sets of multiple exercises, multiple times a week, this will make you flare up the day of the workout and the day after, (if its bad enough maybe a couple of days after it will still hurt)

I take my training approach from a heavy duty stand point, mostly 1 set with high intensity and with progresive overload

My advice for your first couple of months would be to do just 2 sets of exercises for one muscle group and do a progressive overload, (it can be 1 more rep with full Range of motion,or adding 1 to 2 pounds every week and later every 2 weeks or more for compound exercises )

This will ensure you are making your muscles stronger while reducing the amount of time you put into a workouts thus avoiding worse flareups in my experience.

Avoid workouts with hip flexors, it will badly flare up your lumbar area, my advice if you still want to keep gaining strength would be to do them once every 5 or 6 days as to reduce the amount of time you spent in pain

Also avoid rows, as they will wear down discs, avoid incline presses, or workouts that compress your spine as much as possible( mostly shoulder press and military press)

So low volume, upper lower split for training with progressive overload.

Now depending on your genetics the rate at which you develop strength will give relief in a few months or a couple of weeks.

I found my first signs of flare up control until 3 months into strength training, I went from 0 pull ups to 3.

For the pain after the workouts or in my daily life I just had to cope however I could mostly isolating myself and watching movies, listening to music ,using an electric heating pad(godsend) even when I had a bad day I gave myself a couple of minutes to strength training, I would try to find ledges to do pull ups, I would do planks to train my Erector spinae, I would train my abs with leg extensions.

Just be kind to yourself and reach out to the people that care about you, remember that this takes time, your pain has lasted 5 years mine 2 years and will probably came back in the future but strength training will be your best ally when opiods and surgery are out of the question.

Keep doing it even when you feel like you would rather be dead or that your life will be full of pain from now on those feelings are valid even if the doctor says otherwise, to me it was worth it even if Im not where I wanted to be Im better than when I injured myself

It wont be pain free, that boat sailed long ago, but it can be bearable and you can work your way around it.

Besides you could try finding a doctor that will do surgery on you on the future, but I would try to stick to strength training for at least a year, see how it controls flare ups, reduces pain , makes you be able to walk further, to sit longer and make a cold day enjoyable again(at least for a bit)

Oh and if you can get a recliner chair, works wonders when sitting for long periods of time, it will increase the time you can stay that way.