Boy, ain't it the truth? Gardening and sore muscles seem to go hand in hand. Especially as we age.
I remember the good old days when I could work in my garden all day, be tired, and achey and just sleep it off. These days, its an on going soreness all season long. I do a series of Yoga stretches every morning and evening to keep limber. Also,as hard as it is for me, I recognize my limits and pace myself. It takes me much longer to tackle the large projects, such as digging out a new bed, or mulching 2,000 sq ft of bedding space.
I have also gotten better at asking for help, rather than trying to do everything myself. A good backrub always helps too