Brake Problem Bad squeek and loud pop

I changed my brake pads a few weeks ago and after I did the started squeeking. I thought they would stop after a day or so whe they wore in and they kind of did for a few days but then started again and it got progressively worse. When I had my wheels switched the other day i had the shop(firestone) do a brake inspection since it was free, and they said everything was just fine they were only squeeking because the needed to wear in more(its been about 3 weeks since they were changed so that doesnt seem right) and the back pads were about 70% worn. Well that was last monday and today i was driving about 40 the light ahead went red so i started braking they were fine untill i slowed to about 20 then they started squeking as usual but this time right before I came to a stop there was a loud POP noise that came from the front driver side. I pulled into a parking lot right away to look under the car to make sure it wasnt a tie rod or anything else and drove around the parking lot testing the brakes and ABS and they seemed fine(still squeeking). Any suggestions? Also a few days before I changed the pads my car was hit in a parking lot on the front drivers side but very light only put a small crack in the bumper and did not hit near the wheel. could this be related?

never heard of anything like that and from what ive been through i wouldnt believe what firestone said. brake masters did a free inspection on my pads and said they we ok even though they were scratching and i took it to the dealers and they didnt even say anything, they just replaced them. i would say take it to the dealers and see what they say

I just think its kinda weird that a shop would say theres nothing wrong. I was expecting them to say something stupid like I need all new calipers, pads, lines and a master cylinder just so they would get the money there are plenty of shops around here that are like that too.

yea, you would expect them to try and get money from you but eho knows...they might just suck at what they do or be really azy