What does Elixir of Pain reward?

Elixir of Pain gives Recipe: Hot Lion Chops outright, a choice of Gloves of Brawn, Stomping Boots, Firewalker Boots, Trophy Belt, 1,950 experience.

Where does Elixir of Pain start?

Apothecary Lydon in Mulgore offers it.

The quest log lists it at level 24.

No. The quest exists in Classic Era as well.

World of Warcraft: Forever · quest · level 24

A level 24 quest in World of Warcraft: Forever, offered by Apothecary Lydon in Mulgore. Recorded by 3 players running the addon.

Item	Given	Item level	Vendor sell
Recipe: Hot Lion Chops	outright	25	4s 50c
Gloves of Brawn	as a choice	24	7s 14c
Stomping Boots	as a choice	24	9s 22c
Firewalker Boots	as a choice	24	7s 28c
Trophy Belt	as a choice	24

What does Elixir of Pain reward?: Elixir of Pain gives Recipe: Hot Lion Chops outright, a choice of Gloves of Brawn, Stomping Boots, Firewalker Boots, Trophy Belt, 1,950 experience.
Where does Elixir of Pain start?: Apothecary Lydon in Mulgore offers it.
What level is Elixir of Pain?: The quest log lists it at level 24.
Is Elixir of Pain new in WoW Forever?: No. The quest exists in Classic Era as well.

What sells at this level, and what to keep from these rewards, is in the level 20 to 30 gold guide.

Source: what players running the addon saw in the quest windows; the quest text itself stays in the game. Every quest seen · Mulgore