Hi Larry,
I have this as well and I was just diagnosed with Baroreflex failure. This can happen after trauma to the head and neck such as surgery or radiation. I have metastatic thyroid cancer and had 7 weeks of radiation. My cardiologist put me in touch with this doctor at Duke here in NC. This is also related to long covid as well … dysautonomia is the general term for it. It sometimes includes gastro intestinal issues, and cardiac issues combined and I also have issues with horrible anxiety and mast cell activation syndrome where I have sensitivity to medications, smells and sounds. Your autonomic nervous system has had some damage somewhere for most who deal with this, I hope you can find some help and relief soon.
Take care,
Char