worried ! vibrating belly?

worried ! vibrating belly?

I tend not to get worried but I'm laying on my couch with a ton of pelvic pain and pressure. My vagina is so sore (sorry but it is). Anyway me and my husband are laying on the couch watching the voice and my belly out of nowhere just started almost like vibrating. Trembling non stop for about one minute. It was not a kick or a jolting feeling just a light consistent fast tremer. What could this be ? I am very sure that it is not the hiccups. Never had this throughout my entire pregnancy.