In chemistry, is mass and volume the same thing

if not, whats the difference?

They are not the same thing but they are related by density

Density = mass/volume

Mass is the 'amount of stuff' something contains whilst volume is how much space that 'stuff'' occupies.

No, But in chemistry then can be interconverted into either at standard condition.
For ex: 32gm O2 form 22.4 l of gas at STP.