severe pain after nocturnal orgasm?

That must be intense pain to cause shaking and sweating. I did some research and sorted through to find some information on female pelvic pain by Dr. Rodney Anderson and Dr. David Wise, the developers of the Wise-Anderson Protocol for pelvic pain,

They think that most of these conditions, including sexual pain including orgasm and post orgasm discomfort (often the next day), may in some way related to chronic tension or spasm in the muscles of the pelvic basin and fed by anxiety, protective guarding and the habitual tendency to tighten the pelvic muscles.

I suggest you make an appointment with your gynecologist to be evaluated and to discuss your problem.

Maryann