Oh yea scap push ups are awesome actually keep doing those and yes, you're in the correct rep range and sets. But, you dont want to over work the subscapularis... it can strain and even tear. Hmmm, yep.. just remember this... subscapularis, lower/mid traps, rhomboids strengthening and pec stretches. Dont forget to stretch. Foam rolling my upper back and scaps with the rumble roller helps me a lot. If you can, look into a massage therapist.