LoveToKnow lists the upper back as one of the least painful places to get a tattoo, while the pain level for the lower back varies from person to person. The pain level of a tattoo depends on an individual's pain tolerance and the placement of the tattoo.
Tattoos on areas of the body that are fleshier and have less tightly packed nerves are likely to hurt less. Some factors that may predict pain tolerance include how easily the person bruises and the pain level of small injuries, such as stubbing a toe. Every individual has a different pain tolerance and reacts differently.