Hi Beaflower. For me, to learn to drive took a lot of practice, of course. One crucial thing I learned is to never rush anything you are doing. For example, when I was learning to parallel park, other drivers were impatient, and would honk at me. I would just wave them on. Do not let other impatient drivers rush you. If they are in a hurry, they can just go around.
As far as having chest twinges, it may just be anxiety. I, myself, would tell the instructor about my anxiety. And don't forget to take deep breaths whenever you feel tight or anxious. I do know how you feel.