The green lock next to Apple website isn’t there

Doubtful it's a virus.

Make sure your Mac's software is up to date.

Open the App Store then select Updates from the menu.

Also, if you are using Safari to surf the net, you could have a Safari extension or third party plug-in installed that's causing this glitch.

Help here > If Safari is slow, stops responding, quits unexpectedly, or has other issues - Apple Support

Hello mac_pol.17,

What do you get if you click the padlock icon? And then show the certificate? Hold down Shift key, Command Key, and type 4, then draw a box, to take a screenshot of that area of the screen.

No. You need to click the grey padlock. It will display more information about the certificate. Do a screen capture of that. Then, click "Show Certificate" for details. Expand the "Details" item. Take a screen capture of that.

You are using the Avast antivirus software. It adds a "man-in-the-middle" security certificate, intercepting all of your traffic. You can read more about that here: http://www.thesafemac.com/avasts-man-in-the-middle/

Even if I key in apple.com in Safari, I get the "green padlock icon Apple Inc" show in the address field.

It should show "padlock icon" Apple Inc (instead of Apple.com) in the address field.

Do you have anti-virus or something installed on your Mac?

You should worry, but for different reasons. I strongly recommend uninstalling Avast immediately.