Swallowing vis-a-vis the Breath
Breathing must pause for swallowing to happen. Try a simple experiment, pause and swallow first after exhalation, then pause and swallow after inhalation. Determine which of the two you do habitually, it will feel the more natural.
Rationale: Swallowing after exhalation is easier, the thorax is relaxed and there is less pressure in the mediastinum where the esophagus is. Taking a large breath and holding it (to swallow) increases the pressure against swallowing. If the breath is usually taken high in the chest, this is even more the case. Perhaps the tendency to swallow after an in breath represents a fear of drowning or very poor attunement during early feeding experiences.
Source: The author's own self-observation