46 has pnuemonia and just found out she has congestive heart failure. does this mean every time she gets sick fluid will build up around her lungs?

No: Not neccesarily. Obviously there should be a work up of CHF which includes blood work, echo and stress test.

Not exactly: Patients with congestive heart failure develop fluid in the lung tissue as well as outside the lung as one of the complications of congestive heart failure. When the heart is not pumping effectively is does not empty properly, the blood pressure in the lungs is elevated and fluid leaks out of the vessels into the tissues. This can occur whenever the heart failure worsens, like with an infection.