Tips to stay comfortable at work?

So I just recently got a new job, I’ve worked for two days so far and those two days were both ten hour shifts. My manager told me that usually my days will consist of ten hour shifts. We only get a 30 minute lunch break, if that and the entire day we’re on our feet standing, walking around, and putting away inventory. I was just wondering if anyone had any tips to be more comfortable for these shifts. These first two days I’ve been hurting so badly after work and during work, I know a lot of it is because it’s all new but if you have any tips I’d greatly appreciate them!