Only iMessages will send on my iPhone 4s?

I've had my phone for about a year now with no problems, but about a month ago I noticed that when I tried to text someone who doesn't have an iPhone/iMessage, it wouldn't send. I forgot about it for awhile until I tried again today, and it still won't work. I also noticed that I haven't been receiving any regular SMS texts either. I went into settings and SMS messgaing is turned on, and my sister and I are on the same plan with our carrier (AT&T) and she can both send and receive SMS mesagaes. I've tried turning my phone off and back on, which dis nothint. Therefore, I have no idea why they aren't working and I need help!

Added (1). I've also tried turning off iMessage and sending a text.

Who know anything about paypal?

Okay some guy tried to duke me on craigslist he came in picked up my iphone 5 and he payed through paypal and i sent the money off to my moms account as "friends and Family" i wanted to know if he file a dispute will it take the money out of her account, Keep in my mind i'm legit i really sold an iphone 5 and he really came to pick it up but i know paypal show very heavy favoritism to the buyer and not the sellers, so is my money safe in my mom account

Do AT&T stores sell iPhone 5 headphones?

I lost mine and the apple store is to far from my house but there's an AT&T store 2 minutes away. Do they sell them at Walmart too because there's a Walmart about 2 seconds from my house. Any information would be really helpful.

If I buy a AT&T iphone, can I use Verizon or Sprint's SIM card?

I knew AT&T is GSM network, Verizon and Sprint are CDMA network, so AT&T 's iphone can't use Verizon's SIM card?

Added (1). Some people may say verizon is CDMA, it does not need SIM card, but you know the Iphone 4s for Verizon has SIM card slot, so it is for what? Or if I buy iphone 4s can I use all kind of (Verizon, AT&T, Sprint and T-Mobile)SIM cards?

Is there any free app to view mags and books?

I use both iPhone and Samsung and wanted to know if there was a app which could be used to read free books and mags.iBooks is great but it doesn't offer new books for free. I'm willing to jailbreak my iOS or root my android if needed. I can also pay for a service in which I can read all the books I want for a period of time.

Thought about AT&T VS Sprint?

I currently have AT&T (on a family plan) i'm going to get my own plan soon, my 2year ends in april 2014. I use data Alot and texting, not much of a talker.thought about switching to sprint because ill be paying $20 less plus unlimited data than AT&T. But not sure of sprint coverage, data speed compared to AT&T i will be getting either the new iphone when it comes out or the iphone 5 (currently have SamsungGalaxy S2). Would it be a wise choice? Iv been doing reaserch but i'm not sure.

Dropped Iphone 4s in water.ways to dry it out fast?

Welp I had my iphone 4 in my back pocket and as I was pulling down my pants before I used the bathroom my phone dropped out of my pocket in the toilet. I probably got it out in about 1.5 seconds because I was so hectic… Lol. But when I got it out the screen went black… But It was still technically working because I had got several text messages and I could determine who they were from because I had designated a specific vibration you know. Plus I could switch the little switch that you would use to put your phone on silent and still felt the vibration from that. Later my LED light came on and after a while I couldnt feel the vibrations anymore and I'm guessing that's because my phone went dead. Before I buy a replacement. I want to know some EFFECTIVE ways that I could possibly dry my phone out.

Also… I heard the rice trick. Does that really work?

Neck pain, eye sensitivity, and headaches. Why?

So for a week maybe 2 weeks straight I had major neck pains that hit all over my trapezius! I felt like crying! I couldn't even get enough sleep at night, my parents took turns massaging it out with this amazing muscle joint cream thing, they kept pointing out that I had lots of knots and should sleep without a pellow for a while. I also became very irritated with light, and felt like I have photophobia, I wore sunglasses in the house for 2 days I hates the screen of the tv and my iPhone and computers around the house. I also got major headaches and felt really weak, like I have weak joints also and am energyless. This has never happened but it all went away as soon as my menstraul period stopped. I'm 21yrs old, and am switching jobs so I don't have medical benifits at the moment that's why I didn't go to a Dr. Even though my boyfriend insisted on having one of his urgent care Drs check me, I didn't want him to do me any favors. Anyways, could it be just a muscle strain? Or more serious?