I need to get into my i Mac and I see a padlock asking for password I’m stuck get into my iMac and I keep seeing a padlock and asking for password need help

It sounds to me that your Mac is firmware locked

1. Start up from macOS Recovery. During startup, you will be prompted to enter the firmware password.
2. When the utilities window appears, click Utilities in the menu bar, then choose Startup Security Utility or Firmware Password Utility.
3. Click Turn Off Firmware Password.
4. Enter the firmware password again when prompted.
5. Quit the utility, then choose Apple menu  > Restart.

If you cannot remember the firmware password:

If you can't remember your firmware password, schedule an in-person service appointment with an Apple Store or Apple Authorized Service Provider. Bring your Mac to the appointment, and bring your original receipt or invoice as proof of purchase.