Patrice, looks like you well on your way with your machine quilting! A couple of suggestions would be, not to use caffeine prior to quilting and relax. When I started machine quilting, it took me forever cause I would have to take long breaks because of the searing pain in my shoulders and back. Make sure the bed of machine is even with bent elbows. If you have your machine above that level you are putting strain on muscles by being in an unnatural position. This was the single most useful information I received and it has made all the difference.
Keep plugging away, you are doing a great job! I am very glad to see you realize the importance of tongue position. :lol: