Body sore after walking

How old are your sneakers and are you wearing the right kind? Walking/Running shoes are designed specifically for that activity so they provide better support for you. If you walk a lot you should probably get new shoes at least every 6 months or so. Also have you had your gait checked to make sure you are walking correctly? I used to walk all the time, but because I have flat feet and my heels would strike before my toes I ended up with plantar fasciitus in both feet - NOT fun at all.

If your gait is incorrect and you aren't wearing proper footwear, you cause yourself to work harder and tire yourself out. If you feel sharp pains in your feet, don't ignore them! [I ignored the pain I had in my left foot which caused me to change my gait and put more weight on my right foot and that made things a lot worse].

Read up on Overpronation and underpronation and that may help you [ I know there is a video on youtube that demonstrates each one]. There are also things you can do to correct it [orthotic insoles, certain types of shoes, etc.]