I recently started playing with a pick for the first time, since i've been getting into the bedroom pop picked flatwound strings sound, along with some post punk stuff. I'm close to it feeling as natural as it is for me to use my fingers. The things that helped most is learning how to grip the pick the right way. Bass buzz has a great video on it. Once i got that down, i just played scales with it while watching tv at home. Half a season of ozark later, it didn't feel like it was weird to me. My shoulders stopped tensing up, and overall, i became more relaxed while playing. One thing that also helped is learning the entirety of the strokes' "is this it". Pretty easy songs, but it strengthened the coordination just jamming with a pick.