Pop noise under drivers side occasionally when driving and also when reversing

What is your question?

I recently ran up on a curb I didn't see in a parking lot going probably 5 mph. Appeared to just have scraped the underside of the car but now I am hearing a random pop noise when I'm driving but more consistently when i initially put my car in reverse. Feels like its running fine but I'm worried there is damage. Any ideas on what that could be and how much it might costs to fit?