Reason of Trouble in Chest

It is not sincerity to express only what the adverse forces suggest or what you feel when you are in a bad condition, full of obscurity and a wrong outlook. When you are in the Truth, you feel quite the opposite and it is not insincerity to cling to that and recall it. It is only by bringing it back that the Truth can grow in you.

The trouble in your chest comes only from a vital resistance and it continues because you identify yourself with that resistance. It is only by quietude and opening to the Mother that these things can disappear. There is no other way to progress.
If you have not got quietude, you can always aspire first and a sincere aspiration will bring it back.

Ref :  Letters on Yoga Vol. III