Twice a year I have this sudden pain in my chest?
Twice a year I have this sudden pain in my chest, that doesn't allow me to breathe for 5 or 6 seconds.
Putting together your age and the infrequency and character of your pain, this does not sound as if it has a serious cause. The most likely cause is a trapped nerve in your ribcage which is quite a complex 'cage' of bones (the ribs) with nerves, muscles and joints. Obviously a pain in your chest due either to a trapped nerve or cramp in the muscles between the ribs is likely to make it difficult to expand your chest for that brief moment and, therefore, breathing isn't possible for those few seconds. If it becomes more frequent or longer lasting, it would be best to see your GP.