Is it normal to get double vision by pushing on back of eyelid.?

Yes. You can induce astigmatism of the cornea which can cause double vision by pressing on the eye or eyelid. You can also stimulate retinal cells which will leave a scotoma or after image by pressing on the more posterior aspects of the eye.
Double. If you push hard enough on your eyelid, the eyes will not line up together, resulting in double vision. Your brain is trying to line up a picture from each eye, and if you upset that balance, you will see two of everything. Do not do this when driving.