I had a lot of issues with this at a retail job I worked for a few months. It definitely hurt the worst in the first couple of weeks, and then my body started to get used to it. Comfortable shoes definitely help, but they can only do so much. Stretching any chance you get also is going to help you a lot. I managed to just push through the pain, but eventually for me the best solution was to leave the job because it hurt my back too much. My advice is keep at it for a few weeks and if it doesn't feel manageable to you don't force yourself to keep doing it.

Same things that helped RadiantObscurity have helped me, plus wearing a back brace while working sometimes (not a great fix long term as it can contribute to a weak core, but it helps me on particularly bad days). I also stretch first thing when I get home from a shift. It's hard, because I'm so tired, but it helps me to be in less pain the next day. These days I only work that job part time, and I'm hoping to stop altogether soon because it's just not sustainable for me. Some other retail jobs will allow you to sit while you work, and that might be a good option if your current job turns out to be too much for your back. Wishing you the best.

I put a lift in one of my shoes (my doc said my curvature is partially caused by one legs being shorter than the other) and it helped immensely.

my scoliosis is basically gone at this point, its just the back pain thats persisted

I bought crocs shoes for my job. They’re very ugly but extremely comfortable, and were very helpful with reducing my back pain. Also, it’s worth looking into insoles

Get 1 of those adjustable back braces that helps and I use a Tins unit u stick it on wherever it hurts it’s like a Deep tissue massage I ordered one from eBay for $ 19.99 and that works wonders especially at the end of the day when your hurting the most

I worked at the post office for seasonal work one winter, and it was really physically demanding and really long hours. I knew very early on I was gonna have to be very careful to make it through the whole thing(it was 2 months). What ended up working for me was I woke up extra early every morning to do yoga and stretching and make absolutely sure I was lifting correctly my entire shift, even when my legs got so tired from squatting. Even with that though, there was a point where I felt like I wasn't gonna be able to keep going, but somehow I made it through that and it got better from there. However, I don't recommend pushing yourself if you don't feel like your body can handle it. I think I had confidence that I knew when to quit, and I just didn't quite get to that point. I just almost did. Be careful. I picked up some stuff from yoga(I like downward dog, child's pose, and a few things I don't know the names of. I took some yoga classes and just did the stuff that felt good for my body) I found some really good neck stretches on YouTube that I use too. Search around, try stuff, take classes, see what your body responds well to. Stretch gently, don't overdo it! I made that mistake a lot at first. Oh, another thing I learned is if you're standing in one place you should shift your weight around and shuffle, keep relaxed and good posture. It helps if you don't stay stiff. I took some lessons in something called the Alexander Technique that helped me with that. It's a movement therapy thing I think