I think the biggest issue with being an introvert is that you're comfortable being that way. And it's too hard to break out of your comfort zone to change it.
It's a surprisingly easy thing to fix. Start small. Look a complete stranger in the eyes, smile, and say hello. That might sound terrifying, but it isn't. Just a few seconds of "bravery". You'll see it was nothing. Do that a bunch of times, until it's no longer an issue for you. That might be 5 times, it might be 100. But it's easy.
Once saying hello is easy, move on to another comment. Ask the person something about themselves. If you can't think of anything to ask, maybe ask their opinion of something. If you're ANYWHERE that sells food (not a 7-Eleven), find out what they recommend.
That's going to be pretty huge for you, and you'll probably crumble the first few times. But then you'll realize it doesn't fucking matter. You can be as friendly as you want, and in most cases, people will respond with the same energy you give them. Just remember that this is a life change. You need to "force" yourself to do this. Eventually, it's just second nature.
I was in exactly your position for the longest time, then I realized it doesn't fucking matter. Now I'm great talking to anyone about anything. Being an introvert is entirely ego driven. You may not realize it, but you're afraid that other people won't accept you or respond to you, so you're stopping it before they even have a chance. If you're not talking to other people, they can't snub you because you're never putting yourself out there. You CAN get past it. You may never be the life of the party (I doubt I'll ever be that way), but you'll realize just how stress free it is to talk to people. Who gives a shit what a stranger thinks about you? They have NO effect on your life at all. Get comfortable, and it'll be a world of change.
Good luck.
