Haven't held pads for a while now and last night I taught a hard-core class and let about 3 or 4 guys work basic combos on me with focus mits. 

Today my shoulder (I am thinking rot.cuff) feels like it is about to fall OFF.  I have never had this problem in 13 years of training.

Questions - what bad habit have I developed and how can I avoid it? 

Thanks for any input.