Is it normal to want friends ?

I think you might have misunderstood the definition of "introvert".
Contrary to what most people think, an introvert is not simply a person who is shy. In fact, being shy has little to do with being an introvert! Shyness has an element of apprehension, nervousness and anxiety, and while an introvert may also be shy, introversion itself is not shyness. Basically, an introvert is a person who is energized by being alone and whose energy is drained by being around other people.
So if you were to actually be introvert, you wouldn't be trying to make friends you could go places with.

That doesn't matter though, just thought I'd let you know.
To be honest, there isn't a person in the world who has many friends. Most people who claim to have a lot of friends, merely have a large collection of acquaintances, and mistakes them for being friends.
I know a lot of people, and tend to hang out with different people all the time, but in truth, I only have but a single friend. I had two friends once, but I messed up, and lost one of them. But that's another story.

You say you're stuck inside a lot, but is that not your own choice? Obviously, you have atleast SOME friends, what about you have these friends introduce you to some of their acquaintances? You might end up being on good terms with them.
If you want to make friends online, why don't you download an MMO? There are lots of good ones out there, like Eden Eternal. I've stopped playing that game long ago, but I remember I didn't even reach level 10, before I ended up just standing in town, talking with a bunch of people I had met along the way.

Personally I too was alone when I was a child, I still feel lonely sometimes, everyone does. Loneliness is common.

All in all, what you're experiencing is completely normal, and you shouldn't let it get you down.
If you want to meet people, you gotta go out and meet them, that's all there is to it! (:

Much love,

- Nathan