I do now. When I first started playing again last year I had a tech do it, but now I string them myself.
What's your procedure? Are you setting your witness points? What's the nut slot look like? Add pics if you'd like.
Just trying to rule out the simple stuff and you haven't given us much information. The fact that each and every E string (different brands) sounds dull / dead leads me to believe there's a set-up fault or, quite possibly, operator error.
Riis