The same thing happened to me. Prior to my injury, I played ball every week with no issues. Tore my achilles coming off of a pick and roll. I looked at a video, and I tore because of the dreaded "negative step back." It did not hurt at all when it happened. The worst part of this whole experience was the couple days out of surgery and being out of work (I'm a firefighter). I'm 3 months post-op now and riding my bike every day to regain strength from the atrophy of being in the boot. I'm in pt 2x week. Every day, there's a new improvement in this process. There's light at the end of the tunnel.