@hairygrandpa - I am often wrong. Ok, well, not often - but I think you are going about the "getting old" part the wrong way. The issue is that you're very strong and able to contract your muscles with force and in certain patterns, but when moving freely your patterns are not as perfect.
I recommend this to a lot of people who think I'm nuts - but Yin Yoga. Wake up a little early, start your day off with 30-40 minutes of swearing at some b1tch for holding a pose for too long (it starts to hurt) and humbling yourself by rolling around on the floor. Within 2 weeks I bet you will feel much better.
Of course, I did this for 4 months and was sold on it - but then life took over and I haven't been doing what I know I should lately...