I have not used Kratom myself, and never heard of it before your post.
After looking at your links, my advise would be to not try it.
There are no safety controls on any herbal medicines that come into this country.
Therefore, you can never be sure of the quality of safety of the product you buy.
You have no idea if the product was grown with the aid of pesticides that are banned in this country, if the product you are buying is pure or been altered with other additives, nor do you really know of the safety of the product and how it will or will not react with your body.
With the number of sites on the web that are trying to get people to buy this product, it leads me personally to believe that there is a risk in using this herbal attempt to relieve pain.
I wouldn't take the risk of trying any kind of herbal supplement to relieve pain.
Fran