I'm 65 and more sedentary than I should be. This time of year, I start getting outside more, do more walking and more yard work. For the first month, it hurts to get up in the morning. Every year is a little bit harder.
I've found that stretching is a lot more important than it used to be for me. I get a little less flexible every year and lot of what I thought was joint pain is tight tendons. My spouse has dragged me to yoga classes twice a week and that makes a big difference for my lower back, hips and knees. I've found that if I do a thorough routine of stretching at least twice a week, the pain gets much less.
I've also found that you've got to watch the side affects of any medications you might be taking regularly. My doctor did have me on a daily statin because my cholesterol numbers were a little high. I mentioned at my yearly physical that my joints were sore in the morning (which I attributed to old age) and was surprised when he told me that this was a known side affect of statins. After trying a couple of different ones, I finally got him to take me off of them altogether and my pains got much better.