What Causes Vomiting And Muscle Spasms In The Abdomen?

I had cancer 11yrs ago colon cancer i ve been in remission since, i never had a problem moving my bowels as soon as i eat i have no problem .i move my bowels normal at least twice a day. Well last night i had really bad pains and then i started to vomit and i even passed out this went on for about 5 hours as it just was getting worse i went to the hospital an they took a scan they said they had to drain my stomach that i was having contractions due to the scar tissue from 11yrs ago well they drained my stomach for 18hors and then removed the tube from my nose now i am still in the hospital waiting to move my bowels on my own before i can leave i just had a endo/ colon tests done 1week ago all came back fine i just don,t understand how an why out of no where this came about an is this going to be an on going procedure. I,m waiting for my pcp an my gastro dr to call me so i can tell them what,s going on.i would really appreciate so information about why this happened where to go from here a second opinion is alway,s better to have. Thank you,