Unable to take deep breathes. Done now?

I am unable to take deep breathes as i feel something blocking the trachea with pain in chest region near sternum , However i have done 2 pft tests in the past and 2 chest x rays , all normal , i had also done hrct thorax which shows no abnormality except- FEW SUBCENTIMETRIC LYMPH NODES ON PRE TRACHEAL AND PRE CRANIAL REGIONS , which doctors say as normal. i have also done echo and ecg and all are normal , I FEEL as if it is due to something pressing on the wind pipe or maybe due to chest not expanding properly . yesterday on doing dips exercise in tbe gym for a few minutes it felt as the block is removed upon stretching however it came back. WHAT should be done now? i have taken 1.) q mont tab for 2 months 2.) predmet - which gave me relief for one day but the problem was back again 3.) pantop 40 for 7 days