Before or after, whatever works for your life. The overall lifestyle is what is important. Try to be consistent. Honestly I think you might need to focus on muscle growth, do some squats. If you can stress your legs and posterior chain of muscles more in a controlled environment then when you are in the real world it shouldn’t be as painful. You don’t have to go crazy with the weight but you should be tired after doing something like 3 sets of 10. Your muscles will grow and your normal work day won’t seem that strenuous.