Golytely like thing without prescription constipation reliever?

i am 20 years old i have this odd stomach thing that happens every once in awhile where i get labor like pains that are like contractions they are really painful and extreme diarrhea i had to have a colonoscopy a month or two ago and had to take golytely and i did not have that stomach thing happen for a wile and felt better then i normally do for a week or so i am trying to avoid the stomach prob at all cost and if i could get golyely without a prescription i would do that i had no pain what so ever when i took it is there anything out there that works like it that painlessly brings water to the colon and just flushes it out NOT something that contracts the muscles something that flushes