I was discussing a Valentine's present for this other girls with my boss who I thinks but not certain likes me.We also flirt a lot but I never take it serious. She went onto the INTERNET and chooses the one she liked so I decided to buy it treating her like a friend,She then asked me what message I wrote to this other girl. I told I cannot tell you.Now I think I should have not asked her because I may be giving wrong impression.Am I right to think like that?What do you think she is up to asking me that and helping me buy a valentines gift

It could be nothing. She or you could be a flirt and you two could just be fooling around. See how things turn out over the next few days; who knows, it could just be harmless fooling around.

Maybe she was just curious. Don't make a big deal of it.

As your boss it is IMO inappropriate for you two to be flirting with each other.
It may be nothing, but you need to tread lightly. Don't get yourself into a situation that could lead to the loss of your job.