gf not telling me small stuff that shouldn't matter?

so sometimes my gf will not fully tell me stuff, i dont think she lies well in like two situations but just here are my examples.

so one is i left the room to pee and she went on my phone, i know becase i closed all my apps and when i came back i had a few apps open. I asked if she did and she said no evey time. then i was like then why are these apps open then she was like okay yeah i did go on it.

(i dont care that she did it was just she wasn't honest about it that i didnt like)

i forgot the next one i was going toi type, but it ended the same why, she didnt admit untill there was proof.

then just tonight i saw her looking at burgers on red robins website. and i was like, lol why are you looking at food, and she just said i want to see if they still had burger, but then i saw her text her friend an order she wanted from red robin, she was get me this burger this and this, i dont get why she couldn't just say oh my friend is going to get me food and i was seeing waht they have.

i may be overthinking but I dont see why she donest be honesty about little stuff, makes me wonder if she is like that on topics that matter