You shouldn't be getting joint problems standing around all day. If you are getting something like that, these issues might be arising from fatiguing of the muscles from having to support yourself standing all day. When your muscles are fatigued, you end up supporting yourself less with the muscle and more with the joint, so you get weird "wear" patterns, things misaligned slightly. For example, the front of the thigh pulls more on the thigh bone than the rear of the thigh. That can cause kneecap soreness (patellofemoral tracking gets all whack). Muscles in your core can fatigue, and they are also essential to maintaining correct posture.
The fix in that situation would be to work on basic leg and core strength. A set of ankle weights, straight leg raises, side leg raises, calf raises, some basic "good all around" core exercises (forget the crunches, think plank) can really help you avoid joint-related issues from standing all day.
The fix in that situation would be to work on basic leg and core strength. A set of ankle weights, straight leg raises, side leg raises, calf raises, some basic "good all around" core exercises (forget the crunches, think plank) can really help you avoid joint-related issues from standing all day.