From what I can remember about the movie is that there is a group that are trying to o back to the past they like shock them self with some kind of machine that's all I remember

I believe that the movie you are looking for is actually part of a trilogy called "Back to the Future". There is a link to the first part of the first movie below. It that is the correct movie I can give you the other links...


Back to the Future-part 1 - ÊÓƵ - ÔÚÏß¹Û¿´ - ÍÁ¶¹Íø (http://www.tudou.com/programs/view/xSrG2u0mbG0/)

P.S...

Ignore the Chinese subtitles :)

Maybe Timeline (http://www.imdb.com/title/tt0300556/)?

Maybe Twelve Monkeys ? It came out well after the 80's though.

It could be Bill & Ted's Excellent Adventure

Flatliners?
When you say "shock" and "group" it makes me think flatliners. It is with Julia Roberts, Kevin Bacon, one of the Baldwins, Kiefer Sutherland, Oliver Platt.

They go back to their past while flatlining (they're med students I think) and are haunted by the scary unresolved events in their lives.

Flatliners - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Flatliners)