Dog intermittent pain

[Charliejames16]

Twice now a week apart my dog has been acting strange after eating- trembling, lethargic and just not himself! It happened straight after eating and after a few hours is fine again! Anyone else experienced this or any ideas as to what it could be?

Did he eat the same thing both times?

Yes same thing. But eats that every day and only has a reaction on some occasions. Could be his teeth but then chews his toys and hard treat biscuits daily with no discomfort.