There is nothing romantic about pain.

Not the physical kind, when the searing heat rushes through you, pulsing, pulsing, pulsing, a constant reminder that you're still alive - despite your best efforts - and you want to retch up the very dregs of your existence but you don't even have the strength to lift your head. When hands grip around the thing keeping you alive and you feel the cold instantly, your voice caught in your throat so you don't even have the opportunity to cry out. When your team huddles around you and tells you it'll be okay soon, you just have to push through it, it'll pass quickly, but you know as well as they do that pain is a fucking bitch while it lasts, and it always seems like eternity.
At least with physical pain you're allowed to scream your throat raw and shiver and weep and pump drugs into your system to make it all go away.

But this was an altogether different type of pain. And Tony Stark, genius though he might be, had no idea what to do with it.

It should all be okay by now, really. They'd saved the day, hadn't they? And he'd done his fucking martyr impression and flown the giant nuke (he still wanted to throttle whoever's bright idea that was) into the portal and saved them all.

Why didn't he feel like the hero the tabloids said he was?

For fuck's sake. He was Iron Man. Genius, billionaire, playboy, philanthropist. He was supposed to be out there, showing off, absorbing the praise lavished upon him by his devoted public. What else was he to do? He had saved New York, of course. Not alone, but they couldn't have done it without him. Even if it was his tower that had taken the battle to New York in the first place.

But something hurt.

He had the best doctors at his disposal, of course. Hell, even the concerned and meticulous Banner had given him a clean bill of health, bar the exhaustion, which, well, he was Tony Stark. That was nothing new. But this time the bags around his eyes never left (which annoyed him more than he let on - the gossip mags were going to be covered in blown-up pictures and headlines about his complexion if he wasn't careful), and the weight on his shoulders only grew heavier.

Stark knew something was seriously wrong the day he found himself gingerly uncurling his clenched fist and hoping nothing was broken, before hissing in pain and flopping forward to rest his forehead against the cool glass of the mirror he had just punched. He exhaled again, this time in frustration. What the hell could make the man who loved the sound of his own name into one that hated his reflection?