Thanks for posting your query.
Slow down and give your body time to adjust!That kind of speed at your weight puts a lot of stress
on your ligaments and tendons, which take much longer to adapt to exercise than your muscles do. The ligaments and tendons of your knees and hips react to overstress by developing inflammation, thus your pain.
Your legs are going to hurt if you walk alot. try wearing shoes that are healthier for your feet or roll up a sock as tightly as possible and put it in your shoe under your foots arch. this will get some of the pressure off of your heels.
Wishing you good health