burnin chest throat & mouth

for 1 month now. it started in my chest- tightess & burning. and now its in my throat and mouth. i seen my dr she put me on 40mg nexium. i had  blood work done, stress test ,2 breathing test and chest xray PASS ALL TEST. What is wrong with me? because i am not going better. i just seen a new dr 3 days ago. he is a throat dr. he said my throat is dry. that i might have a yeast infection. i am  taking dexamethasone.75mg and clotrimazole 10mg. i still feel the same. what is wrong with me please help... i am not running fever. i cannot eat. i been drinking ensure and eating food a little. one dr said i might have a burning mouth syndrome.