I get those stubbing pains on my ribcage too. It last 5 seconds but boy is it painful.. I know exactly what you mean by those ignorant techs who can't shut their mouth. The first ECG Thomas had, it was the next day after LC diagnosis, the tech asked when are you going to see a Thoracic Surgeon? Hell were still in the state of shock and did not even know what the hell is thoracic surgeon.. errrh...
I wish I had my boxing gloves then.
Hope all goes well with your test