Is it normal to see flashes of light after getting hit in the eye?

It can be. Getting hit in the eye can stimulate the optic nerve, similar to how hitting your ulnar nerve in your elbow (your "funny bone") can cause pain and tingling in your fingers. This can result in an immediate sense of flashes of light. If you have any prolonged visual symptoms, you should see a doc right away.
No but it is common. Flashes of lights may represent a vitreous separation in which case you should follow up with an eye md soon .