If chest pain is alleviated with time and heat, what might the differential diagnosis be?

When considering chest pain that is relieved with time and the application of heat, costochondritis stands out as the most fitting diagnosis in this scenario. Costochondritis is characterized by inflammation of the cartilage connecting the ribs to the sternum, often resulting in localized chest pain. This discomfort can be exacerbated by movement, palpation, or changes in posture, but many patients report a decrease in pain with rest or heat application, making it distinctly responsive to these methods.

In contrast, a peptic ulcer typically presents with pain that is related to eating, with relief coming from antacids or food rather than heat, making it less likely in this case. A hiatal hernia may also present with symptoms related to meals and positions but usually does not benefit from heat application or a period of rest. Similarly, pericarditis can lead to chest pain, but it is more often worsened by lying down and relieved by sitting forward, rather than alleviated by heat. Thus, costochondritis aligns best with the description provided in the question.