Chronic abdominal pain is common among children, and the majority of cases are attributed to functional abdominal pain disorders. One approach to treating these disorders is by using psychological therapies. This clinical trial aims to see how well pre-recorded guided imagery therapy sessions help children's abdominal pain when delivered via a mobile application (app) on a smartphone or tablet. Participants will complete a baseline abdominal pain and stooling diary to determine eligibility and other surveys. Participants who qualify will be placed in one of two groups by chance: * Immediate Treatment Group * Delayed Treatment Group After randomization, the Immediate Treatment Group will get immediate access to the guided imagery therapy (GIT) mobile app intervention. This intervention asks participants to listen to a 10- to 15-minute GIT session 5 out 7 days weekly for 8 weeks in addition to their usual care for their abdominal pain. Then, participants will complete another abdominal pain and stooling diary and other psychometric surveys at the end of this intervention period. After randomization, the Delayed Treatment group will be observed as they wait 8 weeks without app access. During this phase, these participants will continue to treat their abdominal pain in their usual fashion. After the end of this waiting period, participants will complete another abdominal pain and stooling diary and psychometric surveys again before gaining access to the GIT mobile app intervention. As noted previously, the mobile app intervention will ask participants to listen to a 10- to 15-minute GIT session 5 out of 7 days weekly for 8 weeks in addition to their usual care for their abdominal pain. Another abdominal pain and stooling diary and other psychometric surveys will be collected at the end of this app intervention.