Does getting a tattoo on the back hurt?

Depends
The pain you’ll experience while getting a tattoo depends on the part you’re getting the tattoo on. Also, the threshold for pain tolerance varies from person to person, so if you’re jumpy around needles or blood, I recommend you should rethink about getting that tattoo.
What exactly does the needle do?
The most common method of tattooing that we see these days is the electric tattoo machine; which inserts ink into the skin pores with the help of a group of needles that are soldered onto a metal bar, which is fixed to an oscillating unit. The unit rapidly and repeatedly drives the needles in and out of the skin, usually 70-150 times a second. It penetrates about 1/16th of an inch into your skin.
Where Should I Get It
Generally, the tattoo is more painful if applied to areas of the body where there is less muscle and fatty tissue covering bone, like wrists, ankles, chests, and other normally sensitive body areas. Upper arms are usually the least painful, while the ankles and sternum can be quite sensitive. As a rule of thumb, any part that’s too ticklish is likely to be sensitive, hence, painful. But as I said, it varies from person to person.