ITunes won't send music to iPhone?

So i've been downloading music on my laptop and then transfering it to my iPhone throught itunes. It worked perfectly fine before, but today i learnt that you can add a picture to the downloaded song on your phone. So i was doing that on itunes and this pop up came up saying that something wasn't enabled and it took me to setting and i think it was the sound something anyways i couldn't see that there and i ticked everything. Also i chose some setting about backup or something i can't remember. Now i can't send music to my iphone through the cable. I sync it but there's nothing in the app. And i do not have Match or whatever

Make sure the sync Music option is checked on iTunes.
Click on your phone on the iTunes sidebar
Select music
Check the "Sync Music" option

That should solve your problem.