I've had 4 abdominal ct scans in my early 20's for abdominal pain. how likely am i to get cancer from these tests? what signs should i watch for?

Unlikley: Even though you had a lot of radiation with those CT scans it is not enough to cause cancer. Signs of abdominal cancer are nonspecific: sudden weight loss, fatigue, jaundice, sometimes increased abdominal girth, swelling of the abdomen, bleeding bowel or no symptoms at all. Relax try not to be anxious. Anxiety is a big cause of abdominal discomfort.