Shoulder impingement/injury again & again

Anyone in the FB community have any suggestions on preventing shoulder/rotator cuff injuries? I searched past posts & typical responses were to modify workouts. I'm at day 12 of FB Blender after having completed Easily Bored. Have had same injury about 3 times over past year. Can't do downward dogs, planks, jumping jacks, etc. Wonder how to modify jumping jacks & all other warm up & exercises.