HomespunMary, about the tension in your shoulders & neck..... make sure that you check your posture & BREATH. Get up & stretch your muscles every 45 min that you are sitting at your machine. Put some music on with a good beat & you will find that you will have become a free motion quilting master in no time. Well, about 30 hours of practice will help you to feel proficient also.
When I was learing to free motion, I would cut squares about the size of a fat quarter (backing, batting & top) & would practice. That size was really easy to manipulate & build coordination moving the fabric.
I think the most important thing is that you want to learn. If think you can, you will