The "Squier" is Fender's low end, kind of like what a Ford Escort is in comparison to a Lincoln Continental. I use this analogy because most people know what kind of various problems you will have with an Escort, and how few you will have with a Continental. Everything about the Squier is low budget, and mass produced on low pay / high production assembly lines. If you've already resoldered the wiring, then it may be the pick-ups. But keep in mind that all "non-tube" amps will hum when plugged in, which is why pro's use tube amps exclusively, so if it's just a hum, then it's your amp & just get used to it. as for taking to a music store, most stores have a minimum hourly standard, kind of like a mechanic, and it may cost $100 or more to fix or replace parts, so given the retail of a Squier is about $199, this would be like trying to rebuild the engine on a Ford Escort, futile. My suggestion is to save that money and buy a better guitar. Ibanez, and Washburn have specialized in lower end guitars for many years, where as Fender specializes in higher end guitars, not putting focus or labor into beginner models. I teach guitar, and have seen more problems with the Squier starter kits than I can remember. Look up Guitar Center.com and check out some of the Ibanez, for $299 you can get a lot better guitar, and you may be able to trade in the Squier to knock off more money. Good luck!
Jason
September 2009