m not a doctor, I still think that the endoscopy would be a good idea to have done. It may be able to tell you the exact cause of your
stomach pain, chest burning, etc., so that you can be treated properly - treat the CAUSE of the troubles rather than just treating the symptoms.
Again, I'm no doctor, but unless there were severe unforeseen complications with the procedure, any side effects such as nausea, throat pain - of the endoscopy itself should go away after a short time.