Life and pain are two sides of the same coin, or at least that is your experience. You have experienced so much physical pain throughout your life that you have not only got used to it, but you mastered a way of benefiting from it. Pain is what powers your fury, and you want to take it before your allies, because you are the only one able to take on so much of it. Your connection to pain is not only physical, but also mystical, as you can too almost feel what other suffer. Most people that follow this path are people with chronic pains, using it to fuel their rage, or people that are so used to engage in painful situations that it became part of their lives.

Painful Rage

Starting when you choose this path at 3rd level you learn how to benefit from the pain you suffer while you rage. While you are raging, each time you take damage from another creature, roll a d20. If the result on the die is equal to you proficiency bonus or less, you gain a +1 to your damage rolls made with Strength weapon attacks until your rage ends, up to a maximum additional damage equal to your rage damage.

Let me carry your pain

Starting at 6th level when an ally that you can see receives damage within 30 feet of you, you can use your reaction to mystically redirect part of that damage to you. By doing so, your ally receives only half the damage and you suffer equal points of damage to that amount.

Pain Thirst

Starting at 10th level you can convince your enemies to inflict pain to you. Using a bonus action you can try to force an enemy within 5 feet of you to attack you. The target must make a Wisdom saving throw contested with your Strength (Intimidation). If it fails, it must use its reaction to make a melee weapon attack against you. Unless rolling a 1, the attack always hits.

Pain Will

Starting at 14th level whenever you increase your damage using your painful rage you recover as many hit points as your barbarian level.