I'm missing a couple of playlists from my iPhone, but they are still in iTunes?

Recently I added some new music to itunes. I added these songs to my playlist on itunes, but then the playlists i added them to disappeared from my iphone. I tried syncing my phone with my computer, but that didn't work. The songs are still on both my iphone and itunes. The playlists are still in itunes. But they are not on my iphone. These are playlists I use the most and would appreciate any help in getting them back!

Does a text stay displayed on the iphone 5 unless read?

I know that when someone receives a txt that it is shown but i was wondering if it stays there the entire time until it's read and how much of the txt is displayed. For instance, if i sent someone a really long message (5 pages or more) will it show it's entirety?

Switching to iPhone.extra charge?

I currently have a cheap at&t phone and am on my mom's phone plan. My dad just upgraded to an iPhone 5 and doesn't need his iPhone 4 anymore. I was wondering if i switched to use my dads old iPhone would it raise my moms phone bill? My dad said as long as i don't use internet etc outside of Wi-Fi that it won't go up. Is this true or will just switching to the iPhone up the bill?

What are the down sides to jailbreaking your IPhone?

I want to jailbreak my IPhone 4S. I want to know if there are any down sides to jailbreaking it? Some people told me that if I jail break it then my warranty on it is gone. I know the good things about doing it but what are the downsides?

Why won't't my messages go back to iMessage?

My friend and i both have iPhone 4s', and I sent her a text message a few days ago. But even when we both have wi-fi it still sends as a text message. How can i put it back to iMessage?