Question: 21 year old son complaining going on 3 days now of pressure or lump causing discomfort when swallowing. Says throat is not sore, does not have appetite to speak of (compared to normal), is able to go to work in mornings, but upon getting home has gone straight to bed.

Has been unhappy at work for awhile due to circumstances at play there, however, he is probably the 'most tolerated' employee, and is a good, dependable, level-headed worker. It is also known, and has been known for several months, he has other aspirations outside of that company, and boss supports his decision and knows he will be leaving in the near future.
Had family obligations over weekend - (out of town family visiting - all good relationships), but started complaining Saturday afternoon of strange feeling in chest, difficulty swallowing, uncomfortable but not incapacitating. Was able to see girlfriend during the visit and all seems to be fine in that relationship.
He asked how long should he wait before seeing doctor as it was still quite uncomfortable, he's not eating to speak of, and only wants to sleep upon arriving home. 3 days ago he was apparently good to go, making plans with his buddies and seeing the girlfriend - at first complaint I thought maybe catching a cold, or acid reflux, or something that would be explainable and relatively easily treated, but now it's a bit concerning. Girlfriend works with horses a lot (he'll go, but does not really participate) so then I started thinking Lyme disease or something as a result of being out in that environment. As a rule he does NOT get sick (missed one day in elementary school for being 'sick'), otherwise in good health. This is quite unusual for him to be down for this kind of period of time. Should I be more concerned?