The sim card will not pop out. Any suggestions? Thanks

You can not remove the tray or the tray came out and the sim is stuck?

If the tray is stuck take a really thin paper clip and a pair of pliers and make a little hook that will still thread through the hole but you can angle it to catch on the back side and try to pull the sim tray out manually.

Which model iPhone? If you've never removed it before it takes a bit of pushing to release it.

I know, I had one like that too