#1
i changed the strings on my guitar after i put my new bridge pickup in my strat. however, i messed up on the low e and now it is making an annoying fret buzz from the 3rd to 7th fret. its not my neck because i just straightened it the other day. anyone know what it is?

btw i kinda messed up soldering the pickup - it works fine and sounds good but it is not as loud as my other pickups - should i just have a professional do it?
#2
Yes. Take it to the store and get it fixed. Im sure you want to do your new pickups justice, and you may damage your guitar if you try to fix it from now.
#3
get an allen wrench and see the little screws on ur bridge raise them up until it goes away be sure to recheck ur intonation after also