It is possible that you could be experiencing an increased level of stress especially with what has been happening in the world the past 6 months. There are many silent signs of stress that can lead to anxiety that could cause a sensation like that. If you have any difficulty swallowing, or other heart fluttering symptoms, I would be examined by a doctor right away. Otherwise, try doing some breathing exercises, I like the 10 minute breathing meditations on the Calm app, or even some B-vitamins or magnesium could be helpful.

Could be a vascular malformation or a neuromuscular disorder. Best to see ENT. Further evaluation may be indicated, i.e., MRI, etc.