It doesn't want to put music from my computer onto my iPhone 4S

This has been bothering me for months, and I'm p****d.

I've got the music on my computer, and I've added it to my iTunes library. I've plugged in my iPhone (which, another issue: sometimes it doesn't say my iPhone is plugged in, and I have to keep plugging and unplugging it until it does), and it says it's there. I drag the music from my library over to my iPhone's music folder, and it says "Updating files" or whatever, and the music doesn't get put onto my phone.

It's now started saying "Lost connection with iPhone" when I'm not doing anything, also.

iTunes is a horrible program overall and I avoid using it at all costs, but I've got a ton of music on my computer and I can't find another free program that'll transfer my music over. Please help!