I m a tennis professional and used to dealing with workout pains however, this is like nothing I ve ever felt. When I do the downward dog pose (the central pose of my entire yoga routine) I get a tearing/needles feeling on the back of my left heel about an inch from the bottom of my foot . Traditionally I felt this stretch in my hips, hamstrings, and calf , however the pose is now comfortable for all those muscles though now that I m able to progress the pose I have acquired this pain. Also, progress was minimal. I don t feel I m doing too much or going to far. I don t get the pain doing ANY other stretches even ones stretching the calf or hamstring of that leg. When I stop the downward dog stretch (which I ve been tampering with to alleviate this tearing feeling so I don t have to stop) my heel burns for about 5 seconds as I walk it off eventually becoming no pain at all. I don t have ANY pain while doing strenuous exercise or playing tennis, but am worried that this tearing feeling will result in my achilles rupturing (commonish in the tennis world). I added yoga to my regime about 2 months ago and this has only recently started happening. I m excited with how I m feeling on the court with yoga added to my regiment and would be hearbroken if I had to quit.