Just standing is more demanding than many people think. Walking and running give change and often relief via moving muscles. Believe it or not but the discomfort is a great communicator. That is assuming, as you say, you have no injuries. Sharp pain is another matter but lets just say you are feeling discomforts such as feelings like pen pricks, cramps and general discomfort. Those sensations are often telling you where the blockages exist. Try to relax, release and breathe through them. Remember that Master Lin talks of breathing with or through all of your skin. Try visualizing and feeling the breath go through those uncomfortable spots. If you start wiggling, moving or trying to get comfortable you will miss a great opportunity to work through your blockages.
Also make your sessions short at first and build up to longer sessions. Remember there is good, better, best. Even 10-15 minutes of serious work at first is better than none. In time you will find yourself standing for an hour or longer with no discomfort. Be kind to yourself and exercise your patience. Just my thoughts. Hope it helps.
D
