Omg--what an overwhelming response from all of you. What a wonderful group of people on this board. Thank you all for your support, well wishes and help! It took a little time for my response as I was trying some of your suggestions and thinking about others.
Actually my primary machine sits flush in a relatively new style cabinet--Perfexion 851 Quilter's Dream by Horn. I am able to sit right in front of the needle for a more comfortable position in relation to my machine. When I designed my sewing space last year ergonomics was a top priority. Unfortunately there are not many sewing machine furniture options in my area so I bought the cabinet online without trying it out. I do like it a lot, but one thing that is problematic is the design of hte bottom of the cabinet to the rear. It has a support piece of wood that juts out about 3-4 inches and sits parallel to the floor. This prevents me from being able to place my foot pedal far enough toward the back of the cabinet so that my calf and thigh form a 90 degree angle. I think this is the crux of my ankle/leg problem with FMQ. Now I will attempt to respond to your (mostly) wonderful suggestions:
QuiltE, Tartan & Mdegenhart - Unfortunately my primary machine does not have a start/stop button. However I have a small Brother sewing/embroidery machine that does. I tried FMQ on it last night and it was absolutely wonderful. I can't quilt on that machine; it's just too small. But testing with a sandwich enabled me to observe how that would work. A new machine with start/stop might be in my very new future. ;-)
Mandyrose - I'm sorry for your pain.
Hopetoquilt - I really can't use my left foot after sewing for 50 years with my right. Foot pedal is too close already which I think is a large part of my problem, but I will try stretching before and after. I think that would help.
SlightlyOffQuilter - I am sorry for your pain also. I will try your suggestions also--limiting FMQ time and moving around during breaks. I can't mount the pedal on the side of the cabinet because it is too far away from my seating position. Good idea though!
DOTTOMO - Thank you.
Busy fingers - I did try a phone book under each foot. My spine/back is fine. Just my ankle/leg were in pain.
Leatheflea - & sew4nin - Don't ever drink, won't ever drink--I have to answer to a Higher Authority ;-). Tension is not that much of an issue for me. Sometimes I actually find FMQ relaxing. :-)
QuiltE - I think ergonomics is definitely an issue for me with this pain. My calf to thigh angle is probably at about 65 degrees while pushing and holding that pedal--putting strain on all those muscles and tendons. My upper body is fine.
Nativetexan - I will try to find some tutorials; it might help.
Well what I did today was put the old pedal back on my Singer 201 that is mounted in a beautiful art deco period cabinet. Then I reinstalled the pedal in the cabinet to use the knee control. I have tried FMQ on it before and it is amazing, but FAST for a beginner. Using the electronic pedal, I had replaced the original with, on the floor didn't provide enough speed control. The original with knee control seems better. I will try FMQ tomorrow and see. If it works out I'll use my 201 for FMQ until I get a new machine for my H