A shuffle is almost a swing sort of feel, if you listen to twelve bar you'll know what I mean... kinda duh duh.... duh duh.... duh duh.... duh duh (Works better as I can hear it in my head than in print!)
Triplets are exactly what they sound like, notes in threes - happens alot, particularly when playing at speed. Just think of the notes in groups of three.
On Pentatonics, you're probably hearing people using all 5 patterns in a particular key, with which you can get across most of the fret board - look here
Not all solos are pentatonic - many use hybrid scales, or the modes (being a vai fan, I like Lydian). Look here for modal stuff.
This really expands your ability to deliver a face melter over pretty much anything! :D
Check out my music, video, lessons & backing tracks here![br]https://www.renhimself.com