Practicing SM and SDM and the aftermath

Alright. So. Part of my routine that I'm planning includes the monkey drop. I suppose this is the only video that I can show you exactly what it looks like. Although I'm not a fan of this video- I just know that there is no monkey drop instructional video on the site- and if there is an alternate Pole term for this please let me know. Que at 2:50 for the trick: http://www.youtube.com/watch?v=P3Oq3QAYuZ4&feature=player_embedded#at=20 Basically it is a shoulder mount to tucked AG and then  you straighten your knees out (drop move) regrip really fast and dismount slowly. So... Because this is a new move and I'm practicing my SM and SDM a lot and I am practicing them VERY slow. However. I SM with my right shoulder. Strong arm (right) on bottom and then the left on top for my SM and SDM. However. I ALWAYS get this very strange pain and crazy knot that lasts for a few days under my left Scapula (under the sholuder blade). It is so painful I dont even want to do anything  pole related.  Luckily one of my girls is a Spa Sydell Massage therapist so she can just get the knot right out- but I want to prevent it.  Does anyone have any clue why this is happening? Thanks in advance!