repetitive stress injuries!!!!!!
it could be anything........
break up movments
with breaks
with different movments
break up repition frequent repitions
instead of 50 moves of anything
DO 10 -15 then change drill.
10 reps holster to shot dry fire drill surrender position
10 back to target
10 transitions to low port , dry fire
10 kettle bell swings
10 sit ups
10 draw transition to weak hand , dry fire
10 right hand only dry fire
5 box drills
5 forward windmills, 5 backwards , 5 atlas stretch each leg, 10 air squats, 10 reps r/l hand exerciser, shoulder mobilty exercises (google band/brrom stick shoulder mobilty), wrist mobilty exercise/stretch.....
go pet the cats, spend 5 minutes on face book laod 20 rounds .........later rinse repeat... be creative have fun
do you get the idea? there is alot science behind but its also as easy as changing it up
always try and maintain good, and neutral body mechanics as often as possible, check your posture frequently, activate core.
thing is break up mutiple any repetive action but try and break it up movment to be as dissimmilar as possible
learn how to roll/myofascia self release/ use a theracane trade hand massages with partner
if it hurts stop
scale movments to ability
if youy have previous injuries consult a professional before.....