I was just dxed w/ small pericardial effusion. i am short of breath and keep getting low bp and chest pressure. but my doc won't treat. why?

Pericardial eff: Pericardial effusion is never normal so the question here is: why do you have it? The answer likely explains your symptoms. Cardiac tamponade can cause low BP and shortness of breath but your doctor doesn't feel you have this. The treatment is to stick a needle into the pericardial sac and drain the fluid which carries risk (potentially lethal) and shouldn't be done without a valid indication.