What does it mean if a girl talk to you off and on??

well theres this girl ive been talking to some and were real good friends and stuff but its not like were dating or anything.

but we do talk some but not a lot. its weird cuz well talk a few times a week and then we wont talk at all for a while. its not cuz i dont try either. cuz i do call her and she either txt me back or just completely ignores me. it confuses me really bad. and then she called me once a last week while i was traveling just to see how i was doing. and then we didnt talk for a while and then she randomly txt me the most awesome txt ever taht said i just wanted to say hey and that i miss you! and then we havent talked other than texting since then...its weird im telling ya. just wondering if most girls flirt with guys occasionally like taht??What does it mean if a girl talk to you off and on??
no clue