During my last work out and today's workout, I did calf raises with the whole rack (395) and I felt some pain in my upper back (between the shoulder blades). Normally, I do 325 and experience no pain, but with 395 I do. I tend to just deal with it and continue with my exercise and the pain ceases within a couple of minutes. I plan on seeing a doctor to make sure I didn't do any damage to my back because I don't think such pain is normal, but I was wondering if anyone else has experienced anything similar? For reference, I do standing calf raises using the machine with the shoulder pads.