Mri Pulse Oximeter I Seem To Have A Very Noticable Strong Pulse When I Go To Bed, Lean Back In Chairs Etc, Any Ideas?

I seem to have a very noticable strong pulse when I go to bed, lean back in chairs etc, any ideas? - mri pulse oximeter

Been tested by the cardiologists, MRI and ECG / EKG, stress and 3 separate tests, all negative. There is the possibility of gastroesophageal reflux or a hiatal hernia. When I go to bed, I can really feel the pulse in my back, sides and chest. It feels funny, and has been almost two years now. I was told that maybe costochrinditis and heartburn and stress.
Do you see a chiropractor, and he laid back ribs all the time, and my sternum. Hopefully someone has an idea or something similar.