Structural problems due to fire damage

I have a 3 bedroom, two story condo that has fire damage in the basement, which occurred prior to the purchase. Some joists were replace but others were painted to seal the burnt surfaces and others were patched by doubling up or just a short section, many show splitting and other are warped. There are some small hairline cracks showing in the drywall, and there is a significant crack on both sides of one wall in the 2nd level bedroom near the door (door won't close).

I've live here for many years, but now since about mid november the condo is making various noises that to me seem excessive (pops, creaks, tearing sounds). we have had an unusually warm start to winter, hovering above and below zero deg. c. The sounds started around mid november and are now more frequent and some occur each day.

I think this is a structural issue and not just house settling, I need help to find a engineer/contractor to fix it.