Technologies to monitor patients are convenient for patients and can reduce health costs. Chronic pain is a pain that lasts more than 3 months and affects the welfare of patients. Pain is subjective and there are applications to self-report pain, but their adherence rates are low. The purpose of this article is the understanding of the characteristics of technology that helps the adoption of these systems. We have implemented two solutions (mobile application and wearable device), in order to compare them to measure the rate of user acceptance, and also to get feedback about fundamental features of interfaces to report pain levels. To evaluate the two solutions we conducted interviews with 12 people. The results showed that when given the choice between both devices, 67% of the users preferred the wearable device over the mobile application, and 16.5% preferred the mobile application over the wearable device. We also found that a device for reporting pain must be specific to this purpose, aesthetically pleasing and allow users to report easily and at the right time.