Space, or more properly, Space Time, is the "substrate" of the universe, The "stage", so to speak where everything happens. Matter itself is ultimately waves---Waves in space time that make up subatomic Particles which, in turn make up atoms, etc. Large masses tend to BEND Space time, causing Gravity when combined with the motion of Time.
MASS bends space Time in the direction of the 4th Dimension so we do not see the curvature in our 3D context. masses moving in 4D space time will follow the curve of the space and the inertia we feel in our 3D context is what we call GRAVITY.
Your confusion is due to different DEFINITIONS of Space.---The Vacuum is the "space" between astronomical objects, outside the atmosphere. The space that gets "Distorted" is space time where within the universe exists.--a whole different "animal" so to speak, and has at least four dimensions.