Translation:You must be tired from running through my mind all day.
We have to remember that things like pick up lines might be idioms. What might sound very natural in Spanish could sound very weird in English. I still remember when I was learning German years ago that there was a phrase that translated literally as "Who's got the dead bird in their pocket?" which really meant "Who farted?" Understanding this level of Spanish (or German) becomes really advanced and nuanced stuff.