Has anyone had a Reverse Shoulder Replacement?

Has anyone had a Reverse Shoulder replacement surgery with post surgery problems. I am in my 18th week of therapy and still can only lift my arm about 1/3 of where it needs to be. I have several spells a week with a lot of pain. Tonight my arm locked up, I couldn't move it and felt like charlie horses. I go to therapy 2X a week and do workouts 3 days a week at home.