Do you have a Go- Pro or clone? e.g. SJCAM. Even a HD webcam will do.

A posted image or uploaded short vid so we can see what you're doing vs describing would be a help to us helping you. Just the guitar body, neck & fingerboard in frame will suffice.

Also note. From your previous posts, you've just started out. If you've been hammering away with practise most days, a sore shoulder could be attributable to numerous causes from simple overuse of unaccustomed back or shoulder muscles to how you're holding the guitar possibly attributable to (poor?) posture instigated or exacerbated by your seating and leg positioning whilst playing.