really need girl advice

so me and this girl have been friends for a while now. When we first met each other we liked each other now were just best friends. Even though we both went our seperate ways I cant stop and thinking about her. Whenever we hangout it's just constant flirting and seems like she likes me but she has a boyfriend. I been single for a while and she has problems with her boyfriend. So the question is do I try and tell her how i feel or just move on?

Tell her how you feel. Wait for her response. She might like you, and if she does tell her that nothing between you will happen until she breaks up with her boyfriend, if she wants to. End of story.

go and ask, but if not, run the other way.