Currently agonizing blast adds it's modifier to every damage instance caused by Eldritch Blast. This means you get +5 for EB, then +5 for a lightning charge then +5 for Hex.
Don't think this is intended since this makes Eldritch Blast better than any level 3 spell in single target damage, by far.
https://imgur.com/aSw2cw4Here's combat log as proof. I hit Lae'zel for 57 damage.
Eldritch Blast at level 5 does 36 - 70 damage with Hex + Lightning Charges (1 fixed damage and 1 d8 for using up 5 or more).
This is far superior to any level 3 spell in the game in single target, meaning you have no reason to ever use Scorching Ray even with all the fire damage bonus items (the maximum possible damage is higher but on average Eldritch Blast > Scorching Ray level 3). Fireball and Hunger of Hadar can sometimes do more damage since they are massive AoE spells.
I know Eldritch Blast is supposed to be powerful and I love warlocks so that's great, but I think this is a little too powerful.