用腳滾網球 - very effective
First of all, you need to go to a running store to get your shoes. Reebok does not make good running shoes, as far as I know. You may have a cross trainer but you need a pair of running shoes.
Secondly, do a lot of stretch after the walk - while the muscle is warm.
Thirdly, 用腳滾網球. It will be painful at first.
If you have flat feet like I do, then you will need to get inserts.
"越走越不痛。一休息就好痛" exactly, the first step in the morning is the most painful. The first mile of running is too.