Why dose it say sim locked ? I didn’t lock it

If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support

Is your iPhone carrier-locked to a particular phone company?

If it is, and you try to switch to a different phone company, you will find out that the new phone company's SIM card does not work in your phone. You must contact the original carrier and get them to release their lock. Only then will you be able to switch carriers.

How to unlock your iPhone for use with a different carrier - Apple Support

Your tag line says that you have an iPhone 4s. That appears to be a 3G phone. In the U.S., carriers shut down their 3G networks a while back, and in some other parts of the world, carriers may also be shutting down those networks. The day may arrive when, whether your phone is carrier-locked or not, you can no longer make cellular calls using it because there are no longer any cellular networks compatible with it.

Briannebarber wrote:

My phone is stuck in sos mode and now my phone say sim locked

Report the issue to your phone carrier.

• Did you recently update or restore your iPhone?
• Is this a second hand iPhone?
• Was the iPhone hacked or otherwise unlocked by a 3rd party (other than a wireless carrier / service provider) to allow use of other carriers?
• Is it asking for a SIM / PUK code?