My Mother Has The Sensation That Something Is Stuck In

My mother has the sensation that something is stuck in her throat. Her doctor thought is might be related to her thyroid. We saw a specialist who said it is not. When she has this feeling she begins rot panicky and then cannot breathe easily. She has been to the emery room. Heart attacks have been ruled out. Her EKGs were normal. Could anxiety be the cause? What can be done to calm her?