I might have the beginnings of an answer for me. I had a right heart cath done Friday. The pulmonary hypertention I supposedly have (3 echocardiograms) did not ring true. However I had a step up in oxygen saturation where oxygen should be lower indicating a left to right shunt. Oxygenated blood is going back to lungs instead of out to body. Doc said this can definitely cause my symptoms. We know "what" is going on, I am waiting to learn "how"/"where" in the heart-lung path it is occurring.
Once that is determined I will know what comes next.