popping sounds with movement

I have a question, will try to make it short. Husband had a rotator cuff surgery for a 80% tear. He had surgery at the end of November. Its been 4 months and he still has a lot of pain raising his arm. When he does his exercises for PT he has a lot of popping noise and pain. Is that popping sound normal? Is it normal 4 months out to still be in so much pain when trying to raise arm above head?

thanks