This is a question directed to the person who is asked.
Expanding the chest means opening it and extracting what prevents it from comprehending including concerns, worries and pains then filling it with wisdom and knowledge. The Prophet (saws) said:
“When the light enters the heart, it will expand,”
They said: O’ Messenger of Allah, is there a known sign for this? He said:
“Yes, rushing from the house of vanity, rushing to the house of eternity, and preparing for death before its descent.”