You're afraid of pain because you think pain is a problem. In fact, there is no problem with pain. As long as you are alive, you will always have something to hurt, sometimes badly, sometimes weakly... This is normal.
What are beliefs and paradigms? Algorithms for processing and interpreting information coming from the outside world. If information is interpreted as negative, it causes pain. Further, much depends on how exactly to interpret the pain.
There is a threshold of pain and there is a threshold of sensitivity. The intensity of irritation above the threshold of sensitivity ceases to be felt, because it is out of range. The pain threshold is an immunity to irritation, it can be higher or lower. If the pain threshold and the sensitivity threshold are equal, the pain will disappear in principle.
Procrastination and the inability to force yourself to do something is associated with vulnerability to pain and anxiety. The person is afraid that his self-esteem will decrease and this will cause him suffering.
I hadn't run for a long time, and it was only when I started running that I felt pain, but the pain was joyous to me. "It's good for me to get used to the pain,"I thought," it will increase my stamina and give me strength." In anticipation of future strength, I happily ran forward.
Under load increases the sensitivity threshold. By pumping your muscles to the limit, you make them grow. By training pain, you increase the threshold of sensitivity to pain. It also happens with pleasure and with joy.