are u sure they are what you think that is? maybe an inner problem with cervix or something else. go for a checkup!
I just recently read about a woman who has a similar problem to yours, maybe this could be a good jumping off point for you to look into it further.
http://www.newsoftheworld.co.uk/0311_200_orgasms_extra.shtml
I do not think it is related to menopause. Long periods of abstinence may then result in release of sexual tension through dream/orgasms. As I am not a sexologist, I suggest that you ask this question on the Sexuality and Relationships Forum.