Its not so much that the chain is stretched. Stretched is what every chain does and does and does till its stretched out of tolerance.
Your chain is kinked. I had a chain do that once.... here's what happened to the cheap shitty vortex
Which by the way stay away from Vortex.
And ALWAYS replace at the very least the rear sprocket. I would like to see a good picture of yours but it looked like it was actually starting to slim in.
Further a replacement of all 3 components always increases the longevity of your chain. And 2 yrs is not long.
I always had good luck with Renthal sprockets and DiD chains. That being said... check out
sidewinder seems like they have some good stuff as well. There are a couple other brands that offer good sprockets. Alum or Ti centers with steel bolt on teeth rings.