We know that the curvature of spacetime is gravity itself and it is not a force.so,why do we feel our weight in a curve spacetime but not in a straight(I mean not curve) space time like zero gravity space?Why something called "Curvature" produce weight we feel?
When you sit in your F1 car and turn right with 1g of lateral acceleration, you feel a centrifugal force (acceleration) of 1g pulling you in the opposite direction (left, in the car's frame). That is, there is a fictitious force caused by your curving reference frame. This is a Galilean point of view--an accelerated reference frame causes fictitious forces.
Now you are standing still on the Earth, yet you fell 1g pulling you down--but you're not moving--according to Galileo-so what's up? According to Einstein, you are moving--in Spacetime--yes, you are moving forward in time with speed ||c||--and thanks to the Earth's mass, the straight path forward actually curves downward at 1g. [You can prove this by stepping off the ledge of a tall building--but thought experiments are safer].
The surface on which you stand applies a force (per unit mass) of 1g upward that continuously pushes you off this spacetime-straight line--you feel this as gravity pulling you in the opposite direction: down.