I concur with Jesus, to a point, but you don't say wether your fluid is exclusively in your chest, or not. Heart Failure ususally causes swelling in the legs and abdomen, as well as the chest, and everything in between.
In any event, your question should be ask at your next appointment with your Cardiologist, or at least a general practitioner.
I hopw the best for you.
Different reason can produce fluid accumulation even in the Pericardium, the lining that covers the heart...it could be from a virus, or a trauma such heart surgery. I had this and the doctor called it pericarditis, rest and antiinflamatory medication should take care of it for mild cases and it could take a few weeks...my case was due to a virus (?) and in a weeks time the fluid built up so fast that it caused me to pass out...needed emergency surgery, fluid was drained and doctor removed part of the lining so that it can continue to drain....this was 6 years ago today... I have not had any problem since the surgery.....
I imagine you are seeing a cardiologist.......lots of luck...
Different conditions can produce water accumulation in the lungs (Pulmonary Edema), but if you are looking for heart related reasons, Heart Failure is one good candidate to produce it.
Jesus.