Feeling pressure around throat, breathing problem. Lung xrays and ECG - normal. What could it be?

Hi Doctor. I have been feeling pressure around my throat for many months now and it makes it difficult for me to breathe. I need to constantly take in deep breaths, and when I cant do it the second time, I need to try and yawn to induce burps to take in the oxygen and relieve the throat pressure. Its like I can feel the pressure building up in my throat if I don't take in breath. There seems to be something invisible in my throat but I dont know what. My general health and condition is fine, and I really dont know what could be causing this. I have seen a General Practitioner and doctor from Emergency Dept and have done lung xrays and an ECG but the results turn out fine. The doctor from ED said it could be acid reflux but I feel that it has something more to do with my breathing and throat.