98 Jeep Grand Cherokee Brake Problem?

I just recently replaced a tire on my jeep it was the front drivers side tire. As I was driving home from the tire place my car started to pull to the left and it was extremely hard to control. I finally got it home and there was a really awful smell, not like burning rubber but something different. I had someone come look at it and they changed the brakes and also the drivers side front caliper because they said that they could hear it releasing after I parked it. So they did all that and said it should be fine. I drove about a mile and a half and it started to do the pulling to the left and it had a lot of resistance like my brakes were being depressed as I was driving. I took it back to that person and he has no clue what it can be, he said maybe the master brake cylinder. I really need help on ideas of what it might be, if anyone can help with suggestions I would greatly appreciate it! Thanks so much!