What most likely explains a young woman’s experience of swallowing difficulties without pain and subsequent weight loss?

The scenario describes a young woman who is experiencing swallowing difficulties (dysphagia) without pain, accompanied by weight loss. Achalasia is a condition characterized by the inability of the lower esophageal sphincter to relax, leading to obstructive symptoms as food cannot easily pass into the stomach. It is caused by the degeneration of the ganglion cells in the myenteric plexus of the esophagus, which can be associated with an inflammatory process.

In achalasia, patients may report progressive difficulty swallowing solids and liquids, and it is not typically associated with pain, which aligns with the description in the question. The subsequent weight loss is a consequence of the individual avoiding food due to the difficulty experienced during swallowing.

While options like esophageal stricture or cancer could lead to swallowing difficulties and weight loss, they often come with additional symptoms like pain or difficulty specifically with solids or liquids, which aren't indicated here. Acid reflux typically presents with pain or discomfort as well, especially with a burning sensation in the chest (heartburn). Thus, achalasia stands out as the most fitting explanation for the symptoms presented.