Sounds like you need to get into shape there, BR. :p
You're not the only one who thinks that, I do as well. I started with some light walking (1 and 1/4th mile) on one day I was off a week, trouble is I'm on my feet all day (that counts for the foot and knee pain, 18 years of walking on concrete will destroy your feet and knees eventually) and when it comes time to walk, the pain decides to kick in. But I'll keep at it till I'm doing over 2 miles, maybe try getting a bike again to bike my legs back into shape (when I was in school, it was common of me to bike 20 miles or more a day just for shits and giggles, or to visit friends).
My back aches are from years of lifting shit, that takes a toll on your back eventually. Not the best picture of health right now, but far from the worst. Need to also cut down on the soda intake, that stuff right there can leave you feeling drained.