Absolutely you need to acquire good physical technique and there is lots of great advise about that to be had. Something often overlooked by less experienced players (and sometimes by more experienced ones too) is that if you can't hear it in your head well enough to sing it accurately all the physical chops in the world won't help you play it musically. Trying to force your body to do something not perfectly focused in your mind's ear is a frustrating road to stumble down.