You have 2 options---
1---if you want to shoot off the string then put a crimp style nock on the string along with a cushion nock.The cushion nock will take the abuse and pressure.
---nock
---arrow nock
---universal cushion button
---release

2---or you can go with the string loop,arrow sits inside,causing no pinching,and if tied on properly will never slip or move on you.Also saves alot of wear and tear on your serving.

Another thought is,are you using the proper nock for your string?
some nocks are made for 14-16 strand strings and others are for 18 to 22 strand.You might be using the wrong size and not getting a proper crimp--JMO----