Here are three reasons your back might hurt first thing in the morning. First off, it could be your mattress, the quality of your mattress, how old it is, how firm it is. Secondly, physiology. Hydrostatic pressure is something that we deal with when we sleep. Everything has a tendency to rehydrate or swell. That could be a contributing factor as well. Lastly, what position are you sleeping in? Are you sleeping on your side, or your back, or your stomach? A few tips to help you out with that, obviously, lets get you into a firm high-quality mattress. Related physiology, just keep moving, stay active. Stay off of your stomach when you sleep. A lot of us are stomach sleepers. We want to stay off of our stomach. Sleep on your side or your back, and then, ultimately, we want to take it nice and easy in the morning. No bending, no lifting, those types of things. Give our bodies a few minutes to get warmed up.