Alan is most likely to be diagnosed with somatoform disorder.
This is the type of disorder which is a mental illness and also characterized by various types of symptoms such as body pain.
In this scenario, there was no physiological basis for Allan's complaint. This means the illness is a mental one and the availability of symptoms is why somatoform disorder is the most appropriate choice.
Read more about Somatoform disorder here https://brainly.com/question/12164980