My 2 year old son is holding the left side of his stomach below his ribs and seems to be in pain im going to take him to er

Appropriate. He should be seen by your doctor or the emergency room for evaluation.
Taking . Taking him to the emergency room is the appropriate decision. You are right to do this. Any abdominal pain in a child must be taken seriously. Especially concerning signs with abdominal pain would include vomiting, fever, or increase in pain.