My SIM card door won’t open

Just to be sure you are doing it correctly, please review the following article:

• Remove or switch the SIM card in your iPhone or iPad - Apple Support

Is the SIM card and tray the original one you got with this iPhone?

Again, is this the original SIM card and tray that came with your phone or were either a replacement? Has you phone had any issues with battery swelling?

Typically, using something like a paperclip does requires a bit of pressure to push the SIM tray out of the phone. Be sure that you are pushing straight into the small hole and not at an angle.

If you still can't get the SIM tray to open, you will need to make a Genius Bar appointment at your local Apple Store or Apple Authorized Service Provider to have them take a look and provide you with your options.