Thanks for the query to H.C.M. Forum.
Possibilities may be as,
(infection of sternum
), in this condition if you press your sternum just by thumb ,you will feel excruciating pain.
2 May be due to allergic bronchitis
underlying structure of respiratory system.
3 May be due to esophagitis
Without physical examination it is very hard to say something about diagnosis.
Consult a physician and get his opinion.