Would dying of an allergic reaction to water in your lungs be a painful way to die?

I read about someone who died after he was swimming and breathed in a tiny bit of water. The water by itself did not impair his breathing, but 2 hours later the immune system of his lungs over reacted (''secondary drowning'') and his lungs swelled up until he choked to death in bed because his airway, lungs and tongue swelled until his airways shut tight.

Apparently not everyone will have this reaction if they inhale small amounts of water but some people are very sensitive to water in their lungs. Would this of been a painful way to die? Like would it of just been feeling sleepy and not waking up, or choking to death like someone has their hands on your throat?

I literally never heard your lungs can be allergic to water until I read this article today and now I'm afraid of going swimming.