I can sympathize with almost everything people have said. I'm 36, and my joints, back, and muscles feel creakier and more painful with each passing year. It's a rare morning I don't wake up with some sort of pain based on how I slept. (I have a sleep number bed, which I've been able to use to cut down on a lot of it, thank God, but not all).
A lot of it, for me, seems to be circulation (which is part of why cold hurts worse [and I'm in MN right now...]). Exercise is something I should be doing more of, and early in the morning. I find that if I can get moving and get the blood flowing, I feel better most of the day. If I just sit around and don't do anything active, I feel the aches and pains all day.
One thing that I do find funny is that I can still compete very well at volleyball and other things I do -- better than I ever have before because I play regularly -- but I need to stretch more beforehand and limp around for a day after. I remind myself of Yoda in the second prequel movie....hobble in, fly around like a hyperkinetic mofo for a short time, and hobble out....
I do want to throw one thing out quickly for whoever mentioned the eye twitches. i also used to get eye twitches and some other periphery twitches from time to time, and found out I could solve that just by taking magnesium supplements. I highly recommend it if you are having that problem.
As far as for the "couldn't tell you the last time I had sex with my wife" problem, I can't help you there. Let me know if you find a solution to that one. I've got three kids six and under. If it weren't for all the infant feedings, I don't think I'd ever glimpse sight of my wife's breasts anymore.