Having trouble getting your Twitter feed working on Pantheon? Does it work locally but not in your Pantheon environments? If your Twitter solution uses PHP's http_build_query function (as does the Rise theme's front page), you're not going crazy. It's them, not you.
The http_build_query function takes an array and returns a URL encoded query string suitable for use by functions that might find query strings handy, like PHP's curl functions. By default, PHP uses the & character to separate query string parameters, but on Pantheon, this value is set to use the HTML entity & instead. If you try to pass a query string with & instead of &, it will fail.
Fortunately, you can override this value using the third paramter of the call to http_build_query. For example,
http_build_query($my_params, '', '&');
But what if the call is in somebody else's code and you don't want to hack it and cause kitten-death? Well, there is still a potential solution. If you are not relying on the & output from http_build_query elsewhere on your site, you can globally override Pantheon's value with a setting in your site's settings.php file :
That's it. No Twitter token regenerating, no hacking, no hair pulling. Just a one line fix.