I Have Had A Mild Tightness In The Center Of

I have had a mild tightness in the center of my chest for several months. Not sure if it is breast bone or lung. Breathing is okay. No shortness of breath. Pulse normal. Feel fine in all other respects. Take dulara and pulmacort and theophylline for asthma. Also meds for high blood pressure and high cholesterol. Male, 68 yoa, 5' 10", 175 lbs. note, changed from qvar to pulmacort a few months ago.