Dean has problems with his self esteem, and he harms himself...

Never good enough! Never brave enough! Can always become bigger, better, faster, stronger! I have to become bigger, I have to become better, faster and stronger! If I had been that, those kids, those people, everyone would still be alive!

"God! Why can't my life be easy?" because life isn't supposed to be easy dumbass! He then responded himself.

Running was one of Dean's ways to let of steam. Running as fast as he possibly could, feeling the burning sensation in his chest as his lungs felt like they were being tortured.

SPN

This past few days had been quite ordinary, mostly. A demon here, a vengeful spirit there… Not much…

Still, Dean was out here running for a reason. It was everything and all that made him do this. A summary of old and new hunts. All of the 2 354 hunts he had taken part of. 314 of them had ended in innocent blood, nothing else. An additional 462 had ended with someone else than them getting hurt or injured.
Sammy had been hurt on a total of 583 occasions, that included all sorts of injuries, both on and off hunts, but the cue was that Dean hadn't been there to protect him, or at least not well enough!

A sixteen year old shouldn't have faced that number of injuries! You're not doing your job well enough! The thought was haunting Dean every second of every day.

He had to hit something, a wall maybe? Yeah!... he had to beat the hell out of a wall.

A few hundred meters down the road he saw an abandoned warehouse, and entered

SPN

The pain shot through his fist as it connected with the concrete wall.

"Gahh‼" he inhaled sharply, before he gave it another swing. This one with even more force than the last one…

Another intense wave of pain shot through him. Another punch thrown, yet another wave of pain before he crumbled to the ground.

Dean tucked is right hand close to his chest, he tried breathing away the pain. Just like he beat his emotions away a minute ago. Half a minute later he had control, over his breathing, the pain, everything.
Then he moved…

"Son of a BITCH‼‼‼" He breathed heavily trying to get control over the nauseating sensation his stomach gave him, as the bones in his right hand jarred against each other.
"FUCK‼!" that was really all he could think.

Five minutes passed before he managed to move again, this time nursing his injured hand as best as he could. Even moving his elbow hurt, and he was pretty sure he didn't injure that…

SPN

What should I tell Sammy? Dean thought while he looked down at his very swollen and slightly deformed hand. It had instantly taken on a purpleish color, and it still continued to swell… Absolutely a bad sign…

He knew it wasn't his fault, that with everything going to hell… But still, he had to punish himself for it.

It wasn't his fault it happened, but it was his fault he didn't do anything about it! It was his fault he didn't stop it!

He opened the door that lead out, and hissed in pain as he clumsily pushed into the wall with his hand. A small amount of cuss words escaped him, before he took off running in the direction of the motel.

He made it 20 meters before he had to stop and walk instead. Fuck, his hand hurt too much to run!?

SPN

It took him ten minutes to run down to the warehouse, and about thirty-five or forty minutes to get back.

"You back?" Sammy's voice came from the bathroom.
"Yeah, where's dad?"

"I don't know… he left a couple of minutes after you… Said he was gonna grab something to eat…"

"Oh… good…" Sam could hear both the relief and disappointment as he entered the living room. He could also see the tear trails running down his older brothers cheeks.

"What happened?" Sam demanded quickly. And Dean showed him his hand. Not for the first time sporting a boxer's fracture…

"I jumped over a fence, and my pant hooked, I fell and landed on my hand!" Dean answered, and Sam believed him.