I too have difficulty yawning,I start to yawn and can't complete it,it just shuts down and I feel like I can't take a deep breath.sometimes chest and back pain, It takes me 2 or 3 trys to complete a yawn. I have had numerous tests,blood work,cat scans of chest,abdomen,head,cardiac stress,profusion scans,chest xrays,all were normal. I have no allergies.What could be causing this in my case?