I use Options Oracle:
Attachment 13883
This is a Zipped Executable. You will have to extract it.
Once running, go to Config button, then ensure under the General tab that "Online Servers & Stock Exchange Selection" is set to "PLugIn Server US (CBOE)". Select Save
Up at the top, where the Symbol field is, enter "IWM" without the quotes. Underneath that select "Update". Once loaded, at the bottom of the main page, select "Option Pain"
In the popup graph, navigate such that the vertical cursor aligns with the bottom of the curve. At the very bottom of the window, you can read that Max Pain for IWM Options is presently strike = $82.
Regards,
pgd