This has me baffled. I will be honest. And I don’t have any personal experience with what you describe “post procedure”. You say that just since the procedure you are clenching and tightening your muscles like all the time not just during dilation? This is extremely puzzling. This must be more psychological. So I think relaxation techniques are definitely needed here.
That being said, everything is easier said than done. So I would practice this in baby steps. Try hard to use visualization techniques like some of the advice from Heather. Make yourself tighten and relax your muscles at will and then release, until you have more control.
I think a lot of women, including myself, speak about libido and desire as to the aspects of “I haven’t caught up to where my body is physically” but I can only speak for myself. There is a HUGE psychological component to this disorder. However, that being said, ANY CHRONIC pain disorder or any chronic long term physical issue WILL result in a cycle that is hard to break. So even though there is a huge psychological component, no one should make the mistake of believing its “all in our heads”. Because it isn’t.
I hope you can begin working on these muscle clenching issues you are having slowly and that you start to see some progress. Keep us posted as to how you are doing.