“Should I visit ER if I have abdominal pain?”

Depends on   How long have you had the pain.  your age, whether or not you have fever.  How much vomiting and/or diarrhea you have.  Is there blood in your vomit or in your stool?  Have you had previous abdominal surgery?
If your pain persists or your symptoms are not improving go to see a doctor.

Yes