Photons exerting force Since gravity affects photons, and forces always work in pairs.
Does this mean that photons have a resultant force.?
And would we be able to harness this resultant force to move objects using light?
 A: 
Does this mean that photons have a resultant force.? And would we be able to harness this resultant force to move objects using light?

Photons are elementary particles in the standard model of particle physics . They have zero mass, energy=$h*ν$, and spin $1$.
They are described by a four vector of special relativity, i.e., they have energy and momentum, and the length of this four vector, the invariant mass, is zero.


The length of this 4-vector is the rest energy of the particle. The invariance is associated with the fact that the rest mass is the same in any inertial frame of reference. 

As photons have mass zero, they have no rest system.
As they have momentum, when they interact according to the rules of particle interactions, they transfer a dp/dt, i.e. a force, to the particle they interact with.
Here is a video giving an explanation of radiation pressure .
A: 
Does this mean that photons have a resultant force?

Yes it does. If we send a light ray past a massive object and the path of the light ray is changed that means the momentum of the light is changed, and to conserve momentum the momentum of the massive object would also change. It would look like this:

This shows  a star bending the light downwards, and the star will move upwards due to the reaction force. But:

And would we be able to harness this resultant force to move objects using light?

The momentum of light is tiny and for any mass heavy enough to significantly bend a light beam the deflection of the mass would be completely undetectable. So no, we can't use gravitational deflection of light to move objects.
For completeness we should note that you can use light to move objects and this is what optical tweezers do. This technique also exploits the momentum change of the light, but it is unrelated to gravitational deflection of light.
