I get very anxious whenever i have to go somewhere out but once im out i feel better.but prior to that i experience palpitation and stomach problem.could this be agoraphobia?

Yes, agoraphobia is possible among other conditions from the anxiety disorder spectrum. While somewhat typical symptoms for anxiety, palpitations and stomach issues, a somatic origin cannot be ruled out and would suggest discussing your symptoms with your doc to get a better understanding and proper plan.

Please see a Clinical Psychologist with expertise in multiple types of psychotherapy to help you with your fears. It seems the palpitations are related to your fears but to be sure please have a complete physical exam to know if you have any stomach problems. Medication for anxiety prescribed by a Psychiatrist may also be helpful.