If it's fresh after breakup, she doesn't want to send the message that there is still hope for the relationship.
My ex did the same thing, it hurt so much to see the person you love treat you so coldly.
It's best for you to try and heal first before being friends with her. It doesn't work when you are trying to get her back and she just wants to be friends. I would advise a period of no contact until you feel you are ready. When you can accept that your ex may be seeing other people, it's a good chance that you are healed.
No contact is hard, but you really do need it for yourself. Try to keep busy and talk it out with friends. It helps a lot. There will be days where you might take a step back in healing and the pain comes back. Take it slow, there are better days ahead.