Q: every time i try to open a web page I have other sites opening at the same time

It's malware, (not a virus) but easy to remove ...

Download and run the adware removal tool here >   The Safe Mac » Adware Removal Guide

Safe and only takes a minute or two.

Please post a screenshot that shows what you mean. Be careful not to include any private information.

Start a reply to this message. Drag the image file into the editing window to upload it. You can also include text in the reply.

From what you describe you may have inadvertently installed adware. Eradicating it is simple. For an explanation or how this may have occurred, how to avoid it in the future, and for one possible solution read How to install adware.