My abdominal muscles have been hurting today and i have not done any workouts. is it possible i pulled something and didn't know or is it serious?

Possible: Yes it's possible. People are active in sleep and sometimes strain. Muscle tone may be increased during stress, even without exercise. Often we use muscles in the course of a day and don't pay attention or don't remember what we've been doing. If you have no fever, vomiting, or bleeding, it's safe to wait and see if it resolves on it's own a day or so.