Sabali33's Shoulder Pain
Doing the freestyle arm stroke from flat shoulders maybe causing your shoulder pain.
Could rotation be the problem?
Are you able to activate your hip-drive at this point?
How about your two-beat kick?
All these various aspects will produce the needed rotation for you to be able to do your spear arm entry at just the right shoulder angle to hopefully eliminate your shoulder problem.
Suggest you read thru the other forum threads on hip rotation, hip-drive, 2BK, and other related threads, to get a glimpse of the freestyle from a holistic viewpoint.