I’ve been stung by a bee – I trod on the poor thing barefoot – and it hurt A LOT, but quickly subsided after pulling the barb out and no adverse reaction.

I’ve also been stung by a wasp – about a week before the bee sting – on the elbow, it also hurt like hell and my whole arm swelled up and went red.
A couple of years ago I got stung multiple times by wasps – I accidentally walked past their nest and they all came pouring out and chased me, they got my legs and back/torso. I reacted to these too with huge red painful swellings, much bigger and angrier even than horsefly bites, they felt like bruises. Each time it’s taken about a week for them to go down. I’m now absolutely terrified of wasps – knowing how much it hurts and how badly I react, and the fact that they will just sting you for no good reason, I’m practically hysterical if one flies near me

Hard to know what it is from your description but it does sound potentially waspy!