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Some mobs are fine to include in warm ups for your workout others are better following training. When it is something that is better done following training or at another time it is usually indicated in the video. What you are experiencing may have to do with your hand positioning.
These episodes will help:
Pressing Mechanics and The Knee Pushup Up Disaster/Froning and Bailey Edition
Movement Transfer Exercise: The Pushup & The Slingshot
Episode 158: Normal Shoulder Have FULL Range
Have you looked upstream/downstream of where you see the problem to identify other possible places that need work?